diff --git a/x-pack/plugins/translations/translations/ja-JP.json b/x-pack/plugins/translations/translations/ja-JP.json
index 3a15fc6bf2706..10ffbcd5809a8 100644
--- a/x-pack/plugins/translations/translations/ja-JP.json
+++ b/x-pack/plugins/translations/translations/ja-JP.json
@@ -26423,18 +26423,12 @@
     "xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexButton.runReindexLabel": "再インデックスの開始",
     "xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexButton.tryAgainLabel": "再試行",
     "xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexDescription": "再インデックス中はインデックスが読み取り専用です。再インデックスが完了するまでは、ドキュメントの追加、更新、削除ができません。新しいクラスターを再インデックスする必要がある場合は、再インデックスAPIを使用します。{docsLink}",
-    "xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingChecklist.aliasSwapStepTitle": "元のインデックスをエイリアスと交換します。",
     "xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingChecklist.cancelButton.cancelLabel": "キャンセル",
     "xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingChecklist.cancelButton.cancelledLabel": "キャンセル済み",
     "xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingChecklist.cancelButton.cancellingLabel": "キャンセル中…",
     "xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingChecklist.cancelButton.errorLabel": "キャンセルできませんでした",
     "xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingChecklist.cancelledTitle": "再インデックスはキャンセルされました。",
-    "xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingChecklist.createIndexStepTitle": "新しいインデックスを作成します。",
-    "xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingChecklist.inProgress.aliasSwapStepTitle": "元のインデックスをエイリアスと交換しています。",
-    "xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingChecklist.inProgress.createIndexStepTitle": "新しいインデックスを作成しています。",
-    "xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingChecklist.inProgress.readonlyStepTitle": "元のインデックスを読み取り専用に設定しています。",
     "xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingChecklist.inProgress.reindexingDocumentsStepTitle": "ドキュメントを再インデックスしています。",
-    "xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingChecklist.readonlyStepTitle": "元のインデックスを読み取り専用に設定します。",
     "xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingChecklist.reindexingDocumentsStepTitle": "ドキュメントのインデックスを作成します。",
     "xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingChecklistTitle": "プロセスを再インデックス中",
     "xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingFailedCalloutTitle": "再インデックスエラー",
diff --git a/x-pack/plugins/translations/translations/zh-CN.json b/x-pack/plugins/translations/translations/zh-CN.json
index 987a9bfc27f80..eaa6c6f1d9abd 100644
--- a/x-pack/plugins/translations/translations/zh-CN.json
+++ b/x-pack/plugins/translations/translations/zh-CN.json
@@ -26878,18 +26878,12 @@
     "xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexButton.runReindexLabel": "启动重新索引",
     "xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexButton.tryAgainLabel": "重试",
     "xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexDescription": "重新索引期间，索引将处于只读状态。在重新索引完成之前，您无法添加、更新或删除文档。如果需要重新索引到新集群，请使用重新索引 API。{docsLink}",
-    "xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingChecklist.aliasSwapStepTitle": "交换具有别名的原始索引。",
     "xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingChecklist.cancelButton.cancelLabel": "取消",
     "xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingChecklist.cancelButton.cancelledLabel": "已取消",
     "xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingChecklist.cancelButton.cancellingLabel": "正在取消……",
     "xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingChecklist.cancelButton.errorLabel": "无法取消",
     "xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingChecklist.cancelledTitle": "重新索引已取消。",
-    "xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingChecklist.createIndexStepTitle": "创建新索引。",
-    "xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingChecklist.inProgress.aliasSwapStepTitle": "正在交换具有别名的原始索引。",
-    "xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingChecklist.inProgress.createIndexStepTitle": "正在创建新索引。",
-    "xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingChecklist.inProgress.readonlyStepTitle": "正在将原始索引设置为只读。",
     "xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingChecklist.inProgress.reindexingDocumentsStepTitle": "正在重新索引文档。",
-    "xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingChecklist.readonlyStepTitle": "将原始索引设置为只读。",
     "xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingChecklist.reindexingDocumentsStepTitle": "索引文档。",
     "xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingChecklistTitle": "重新索引过程",
     "xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingFailedCalloutTitle": "重新索引错误",
diff --git a/x-pack/plugins/upgrade_assistant/__jest__/client_integration/es_deprecations/default_deprecation_flyout.test.ts b/x-pack/plugins/upgrade_assistant/__jest__/client_integration/es_deprecations/default_deprecation_flyout.test.ts
index fdd8a1c993937..5566ec1d17e2b 100644
--- a/x-pack/plugins/upgrade_assistant/__jest__/client_integration/es_deprecations/default_deprecation_flyout.test.ts
+++ b/x-pack/plugins/upgrade_assistant/__jest__/client_integration/es_deprecations/default_deprecation_flyout.test.ts
@@ -27,6 +27,16 @@ describe('Default deprecation flyout', () => {
       jobId: MOCK_JOB_ID,
       status: 'idle',
     });
+    httpRequestsMockHelpers.setReindexStatusResponse({
+      reindexOp: null,
+      warnings: [],
+      hasRequiredPrivileges: true,
+      meta: {
+        indexName: 'foo',
+        reindexName: 'reindexed-foo',
+        aliases: [],
+      },
+    });
 
     await act(async () => {
       testBed = await setupElasticsearchPage({ isReadOnlyMode: false });
diff --git a/x-pack/plugins/upgrade_assistant/__jest__/client_integration/es_deprecations/deprecations_list.test.ts b/x-pack/plugins/upgrade_assistant/__jest__/client_integration/es_deprecations/deprecations_list.test.ts
index 3b8a756b8e64c..49c084eb9f27d 100644
--- a/x-pack/plugins/upgrade_assistant/__jest__/client_integration/es_deprecations/deprecations_list.test.ts
+++ b/x-pack/plugins/upgrade_assistant/__jest__/client_integration/es_deprecations/deprecations_list.test.ts
@@ -34,6 +34,16 @@ describe('ES deprecations table', () => {
       jobId: MOCK_JOB_ID,
       status: 'idle',
     });
+    httpRequestsMockHelpers.setReindexStatusResponse({
+      reindexOp: null,
+      warnings: [],
+      hasRequiredPrivileges: true,
+      meta: {
+        indexName: 'foo',
+        reindexName: 'reindexed-foo',
+        aliases: [],
+      },
+    });
 
     await act(async () => {
       testBed = await setupElasticsearchPage({ isReadOnlyMode: false });
diff --git a/x-pack/plugins/upgrade_assistant/__jest__/client_integration/es_deprecations/index_settings_deprecation_flyout.test.ts b/x-pack/plugins/upgrade_assistant/__jest__/client_integration/es_deprecations/index_settings_deprecation_flyout.test.ts
index f62d24081ed56..f032c34040bfe 100644
--- a/x-pack/plugins/upgrade_assistant/__jest__/client_integration/es_deprecations/index_settings_deprecation_flyout.test.ts
+++ b/x-pack/plugins/upgrade_assistant/__jest__/client_integration/es_deprecations/index_settings_deprecation_flyout.test.ts
@@ -28,6 +28,16 @@ describe('Index settings deprecation flyout', () => {
       jobId: MOCK_JOB_ID,
       status: 'idle',
     });
+    httpRequestsMockHelpers.setReindexStatusResponse({
+      reindexOp: null,
+      warnings: [],
+      hasRequiredPrivileges: true,
+      meta: {
+        indexName: 'foo',
+        reindexName: 'reindexed-foo',
+        aliases: [],
+      },
+    });
 
     await act(async () => {
       testBed = await setupElasticsearchPage({ isReadOnlyMode: false });
diff --git a/x-pack/plugins/upgrade_assistant/__jest__/client_integration/es_deprecations/ml_snapshots_deprecation_flyout.test.ts b/x-pack/plugins/upgrade_assistant/__jest__/client_integration/es_deprecations/ml_snapshots_deprecation_flyout.test.ts
index b24cd5a69a28e..11bb27bb8b331 100644
--- a/x-pack/plugins/upgrade_assistant/__jest__/client_integration/es_deprecations/ml_snapshots_deprecation_flyout.test.ts
+++ b/x-pack/plugins/upgrade_assistant/__jest__/client_integration/es_deprecations/ml_snapshots_deprecation_flyout.test.ts
@@ -30,6 +30,16 @@ describe('Machine learning deprecation flyout', () => {
       jobId: MOCK_JOB_ID,
       status: 'idle',
     });
+    httpRequestsMockHelpers.setReindexStatusResponse({
+      reindexOp: null,
+      warnings: [],
+      hasRequiredPrivileges: true,
+      meta: {
+        indexName: 'foo',
+        reindexName: 'reindexed-foo',
+        aliases: [],
+      },
+    });
 
     await act(async () => {
       testBed = await setupElasticsearchPage({ isReadOnlyMode: false });
diff --git a/x-pack/plugins/upgrade_assistant/__jest__/client_integration/es_deprecations/reindex_deprecation_flyout.test.ts b/x-pack/plugins/upgrade_assistant/__jest__/client_integration/es_deprecations/reindex_deprecation_flyout.test.ts
index 3c6fe0e5f5329..25742958aa243 100644
--- a/x-pack/plugins/upgrade_assistant/__jest__/client_integration/es_deprecations/reindex_deprecation_flyout.test.ts
+++ b/x-pack/plugins/upgrade_assistant/__jest__/client_integration/es_deprecations/reindex_deprecation_flyout.test.ts
@@ -7,17 +7,28 @@
 
 import { act } from 'react-dom/test-utils';
 
+import { ReindexStatus, ReindexStep, ReindexStatusResponse } from '../../../common/types';
 import { setupEnvironment } from '../helpers';
 import { ElasticsearchTestBed, setupElasticsearchPage } from './es_deprecations.helpers';
 import { esDeprecationsMockResponse, MOCK_SNAPSHOT_ID, MOCK_JOB_ID } from './mocked_responses';
-import { ReindexStatus, ReindexStep } from '../../../common/types';
+
+const defaultReindexStatusMeta: ReindexStatusResponse['meta'] = {
+  indexName: 'foo',
+  reindexName: 'reindexed-foo',
+  aliases: [],
+};
 
 // Note: The reindexing flyout UX is subject to change; more tests should be added here once functionality is built out
 describe('Reindex deprecation flyout', () => {
   let testBed: ElasticsearchTestBed;
   const { server, httpRequestsMockHelpers } = setupEnvironment();
 
+  beforeAll(() => {
+    jest.useFakeTimers();
+  });
+
   afterAll(() => {
+    jest.useRealTimers();
     server.restore();
   });
 
@@ -29,6 +40,16 @@ describe('Reindex deprecation flyout', () => {
       jobId: MOCK_JOB_ID,
       status: 'idle',
     });
+    httpRequestsMockHelpers.setReindexStatusResponse({
+      reindexOp: null,
+      warnings: [],
+      hasRequiredPrivileges: true,
+      meta: {
+        indexName: 'foo',
+        reindexName: 'reindexed-foo',
+        aliases: [],
+      },
+    });
 
     await act(async () => {
       testBed = await setupElasticsearchPage({ isReadOnlyMode: false });
@@ -54,6 +75,7 @@ describe('Reindex deprecation flyout', () => {
       reindexOp: null,
       warnings: [],
       hasRequiredPrivileges: true,
+      meta: defaultReindexStatusMeta,
     });
 
     await act(async () => {
@@ -113,6 +135,7 @@ describe('Reindex deprecation flyout', () => {
         },
         warnings: [],
         hasRequiredPrivileges: true,
+        meta: defaultReindexStatusMeta,
       });
 
       await act(async () => {
@@ -137,6 +160,7 @@ describe('Reindex deprecation flyout', () => {
         },
         warnings: [],
         hasRequiredPrivileges: true,
+        meta: defaultReindexStatusMeta,
       });
 
       await act(async () => {
@@ -148,7 +172,7 @@ describe('Reindex deprecation flyout', () => {
 
       await actions.table.clickDeprecationRowAt('reindex', 0);
 
-      expect(find('reindexChecklistTitle').text()).toEqual('Reindexing in progress… 31%');
+      expect(find('reindexChecklistTitle').text()).toEqual('Reindexing in progress… 30%');
       expect(exists('cancelReindexingDocumentsButton')).toBe(true);
     });
 
@@ -161,6 +185,7 @@ describe('Reindex deprecation flyout', () => {
         },
         warnings: [],
         hasRequiredPrivileges: true,
+        meta: defaultReindexStatusMeta,
       });
 
       await act(async () => {
@@ -172,7 +197,7 @@ describe('Reindex deprecation flyout', () => {
 
       await actions.table.clickDeprecationRowAt('reindex', 0);
 
-      expect(find('reindexChecklistTitle').text()).toEqual('Reindexing in progress… 95%');
+      expect(find('reindexChecklistTitle').text()).toEqual('Reindexing in progress… 90%');
       expect(exists('cancelReindexingDocumentsButton')).toBe(false);
     });
 
@@ -185,19 +210,30 @@ describe('Reindex deprecation flyout', () => {
         },
         warnings: [],
         hasRequiredPrivileges: true,
+        meta: defaultReindexStatusMeta,
       });
 
       await act(async () => {
         testBed = await setupElasticsearchPage({ isReadOnlyMode: false });
       });
 
-      testBed.component.update();
-      const { actions, find, exists } = testBed;
+      const { actions, find, exists, component } = testBed;
+      component.update();
 
       await actions.table.clickDeprecationRowAt('reindex', 0);
 
-      expect(find('reindexChecklistTitle').text()).toEqual('Reindexing process');
+      expect(find('reindexChecklistTitle').text()).toEqual('Reindexing in progress… 95%');
       expect(exists('cancelReindexingDocumentsButton')).toBe(false);
+
+      // We have put in place a "fake" fifth step to delete the original index
+      // In reality that was done in the last step (when the alias was created),
+      // but for the user we will display it as a separate reindex step
+      await act(async () => {
+        jest.advanceTimersByTime(1000);
+      });
+      component.update();
+
+      expect(find('reindexChecklistTitle').text()).toEqual('Reindexing process');
     });
   });
 });
diff --git a/x-pack/plugins/upgrade_assistant/common/types.ts b/x-pack/plugins/upgrade_assistant/common/types.ts
index 89afa05dfe222..02e8880d117f1 100644
--- a/x-pack/plugins/upgrade_assistant/common/types.ts
+++ b/x-pack/plugins/upgrade_assistant/common/types.ts
@@ -28,6 +28,8 @@ export enum ReindexStep {
   reindexStarted = 40,
   reindexCompleted = 50,
   aliasCreated = 60,
+  originalIndexDeleted = 70,
+  existingAliasesUpdated = 80,
 }
 
 export enum ReindexStatus {
@@ -41,7 +43,20 @@ export enum ReindexStatus {
   fetchFailed,
 }
 
+export interface ReindexStatusResponse {
+  meta: {
+    indexName: string;
+    reindexName: string;
+    // Array of aliases pointing to the index being reindexed
+    aliases: string[];
+  };
+  warnings?: ReindexWarning[];
+  reindexOp?: ReindexOperation;
+  hasRequiredPrivileges?: boolean;
+}
+
 export const REINDEX_OP_TYPE = 'upgrade-assistant-reindex-operation';
+
 export interface QueueSettings extends SavedObjectAttributes {
   /**
    * A Unix timestamp of when the reindex operation was enqueued.
@@ -106,7 +121,8 @@ export interface ReindexOperation extends SavedObjectAttributes {
 export type ReindexSavedObject = SavedObject<ReindexOperation>;
 
 // 7.0 -> 8.0 warnings
-export type ReindexWarningTypes = 'customTypeName' | 'indexSetting';
+export type ReindexWarningTypes = 'customTypeName' | 'indexSetting' | 'replaceIndexWithAlias';
+
 export interface ReindexWarning {
   warningType: ReindexWarningTypes;
   /**
diff --git a/x-pack/plugins/upgrade_assistant/public/application/components/es_deprecations/deprecation_types/reindex/context.tsx b/x-pack/plugins/upgrade_assistant/public/application/components/es_deprecations/deprecation_types/reindex/context.tsx
index 2d34253d2c426..3d4459e7380b7 100644
--- a/x-pack/plugins/upgrade_assistant/public/application/components/es_deprecations/deprecation_types/reindex/context.tsx
+++ b/x-pack/plugins/upgrade_assistant/public/application/components/es_deprecations/deprecation_types/reindex/context.tsx
@@ -5,7 +5,7 @@
  * 2.0.
  */
 
-import React, { useEffect, createContext, useContext } from 'react';
+import React, { createContext, useContext } from 'react';
 
 import { ApiService } from '../../../../lib/api';
 import { useReindexStatus, ReindexState } from './use_reindex_state';
@@ -37,16 +37,11 @@ export const ReindexStatusProvider: React.FunctionComponent<Props> = ({
   indexName,
   children,
 }) => {
-  const { reindexState, startReindex, cancelReindex, updateStatus } = useReindexStatus({
+  const { reindexState, startReindex, cancelReindex } = useReindexStatus({
     indexName,
     api,
   });
 
-  useEffect(() => {
-    updateStatus();
-    // eslint-disable-next-line react-hooks/exhaustive-deps
-  }, []);
-
   return (
     <ReindexContext.Provider
       value={{
diff --git a/x-pack/plugins/upgrade_assistant/public/application/components/es_deprecations/deprecation_types/reindex/flyout/__snapshots__/checklist_step.test.tsx.snap b/x-pack/plugins/upgrade_assistant/public/application/components/es_deprecations/deprecation_types/reindex/flyout/__snapshots__/checklist_step.test.tsx.snap
index f3a1723c9c6ea..ef7942942562c 100644
--- a/x-pack/plugins/upgrade_assistant/public/application/components/es_deprecations/deprecation_types/reindex/flyout/__snapshots__/checklist_step.test.tsx.snap
+++ b/x-pack/plugins/upgrade_assistant/public/application/components/es_deprecations/deprecation_types/reindex/flyout/__snapshots__/checklist_step.test.tsx.snap
@@ -37,6 +37,11 @@ exports[`ChecklistFlyout renders 1`] = `
           "hasRequiredPrivileges": true,
           "lastCompletedStep": undefined,
           "loadingState": 1,
+          "meta": Object {
+            "aliases": Array [],
+            "indexName": "myIndex",
+            "reindexName": "reindexed-myIndex",
+          },
           "reindexTaskPercComplete": null,
           "reindexWarnings": Array [],
           "status": undefined,
diff --git a/x-pack/plugins/upgrade_assistant/public/application/components/es_deprecations/deprecation_types/reindex/flyout/checklist_step.test.tsx b/x-pack/plugins/upgrade_assistant/public/application/components/es_deprecations/deprecation_types/reindex/flyout/checklist_step.test.tsx
index 705b4aa906bff..d8e95cd2456de 100644
--- a/x-pack/plugins/upgrade_assistant/public/application/components/es_deprecations/deprecation_types/reindex/flyout/checklist_step.test.tsx
+++ b/x-pack/plugins/upgrade_assistant/public/application/components/es_deprecations/deprecation_types/reindex/flyout/checklist_step.test.tsx
@@ -54,6 +54,11 @@ describe('ChecklistFlyout', () => {
       errorMessage: null,
       reindexWarnings: [],
       hasRequiredPrivileges: true,
+      meta: {
+        indexName: 'myIndex',
+        reindexName: 'reindexed-myIndex',
+        aliases: [],
+      },
     } as ReindexState,
   };
 
diff --git a/x-pack/plugins/upgrade_assistant/public/application/components/es_deprecations/deprecation_types/reindex/flyout/container.tsx b/x-pack/plugins/upgrade_assistant/public/application/components/es_deprecations/deprecation_types/reindex/flyout/container.tsx
index ab2ec0d633323..809f47b4a295f 100644
--- a/x-pack/plugins/upgrade_assistant/public/application/components/es_deprecations/deprecation_types/reindex/flyout/container.tsx
+++ b/x-pack/plugins/upgrade_assistant/public/application/components/es_deprecations/deprecation_types/reindex/flyout/container.tsx
@@ -64,6 +64,7 @@ export const ReindexFlyout: React.FunctionComponent<ReindexFlyoutProps> = ({
   const flyoutContents = showWarningsStep ? (
     <WarningsFlyoutStep
       warnings={reindexState.reindexWarnings ?? []}
+      meta={reindexState.meta}
       hideWarningsStep={() => setShowWarningsStep(false)}
       continueReindex={() => {
         setShowWarningsStep(false);
diff --git a/x-pack/plugins/upgrade_assistant/public/application/components/es_deprecations/deprecation_types/reindex/flyout/progress.test.tsx b/x-pack/plugins/upgrade_assistant/public/application/components/es_deprecations/deprecation_types/reindex/flyout/progress.test.tsx
index 1ee4cf2453bdc..5bf9a394f9738 100644
--- a/x-pack/plugins/upgrade_assistant/public/application/components/es_deprecations/deprecation_types/reindex/flyout/progress.test.tsx
+++ b/x-pack/plugins/upgrade_assistant/public/application/components/es_deprecations/deprecation_types/reindex/flyout/progress.test.tsx
@@ -9,6 +9,7 @@ import { shallow } from 'enzyme';
 import React from 'react';
 
 import { ReindexStatus, ReindexStep } from '../../../../../../../common/types';
+import { LoadingState } from '../../../../types';
 import type { ReindexState } from '../use_reindex_state';
 import { ReindexProgress } from './progress';
 
@@ -22,6 +23,12 @@ describe('ReindexProgress', () => {
             status: ReindexStatus.inProgress,
             reindexTaskPercComplete: null,
             errorMessage: null,
+            loadingState: LoadingState.Success,
+            meta: {
+              indexName: 'foo',
+              reindexName: 'reindexed-foo',
+              aliases: [],
+            },
           } as ReindexState
         }
         cancelReindex={jest.fn()}
@@ -52,17 +59,29 @@ describe('ReindexProgress', () => {
               Object {
                 "status": "inProgress",
                 "title": <FormattedMessage
-                  defaultMessage="Setting original index to read-only."
+                  defaultMessage="Setting {indexName} index to read-only."
                   id="xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingChecklist.inProgress.readonlyStepTitle"
-                  values={Object {}}
+                  values={
+                    Object {
+                      "indexName": <EuiCode>
+                        foo
+                      </EuiCode>,
+                    }
+                  }
                 />,
               },
               Object {
                 "status": "incomplete",
                 "title": <FormattedMessage
-                  defaultMessage="Create new index."
+                  defaultMessage="Create {reindexName} index."
                   id="xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingChecklist.createIndexStepTitle"
-                  values={Object {}}
+                  values={
+                    Object {
+                      "reindexName": <EuiCode>
+                        reindexed-foo
+                      </EuiCode>,
+                    }
+                  }
                 />,
               },
               Object {
@@ -73,6 +92,12 @@ describe('ReindexProgress', () => {
                     Object {
                       "errorMessage": null,
                       "lastCompletedStep": 0,
+                      "loadingState": 1,
+                      "meta": Object {
+                        "aliases": Array [],
+                        "indexName": "foo",
+                        "reindexName": "reindexed-foo",
+                      },
                       "reindexTaskPercComplete": null,
                       "status": 0,
                     }
@@ -82,9 +107,32 @@ describe('ReindexProgress', () => {
               Object {
                 "status": "incomplete",
                 "title": <FormattedMessage
-                  defaultMessage="Swap original index with alias."
-                  id="xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingChecklist.aliasSwapStepTitle"
-                  values={Object {}}
+                  defaultMessage="Create {indexName} alias for {reindexName} index."
+                  id="xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingChecklist.aliasCreatedStepTitle"
+                  values={
+                    Object {
+                      "indexName": <EuiCode>
+                        foo
+                      </EuiCode>,
+                      "reindexName": <EuiCode>
+                        reindexed-foo
+                      </EuiCode>,
+                    }
+                  }
+                />,
+              },
+              Object {
+                "status": "incomplete",
+                "title": <FormattedMessage
+                  defaultMessage="Delete original {indexName} index."
+                  id="xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingChecklist.originalIndexDeletedStepTitle"
+                  values={
+                    Object {
+                      "indexName": <EuiCode>
+                        foo
+                      </EuiCode>,
+                    }
+                  }
                 />,
               },
             ]
@@ -103,6 +151,12 @@ describe('ReindexProgress', () => {
             status: ReindexStatus.failed,
             reindexTaskPercComplete: 1,
             errorMessage: `This is an error that happened on alias switch`,
+            loadingState: LoadingState.Success,
+            meta: {
+              indexName: 'foo',
+              reindexName: 'reindexed-foo',
+              aliases: [],
+            },
           } as ReindexState
         }
         cancelReindex={jest.fn()}
diff --git a/x-pack/plugins/upgrade_assistant/public/application/components/es_deprecations/deprecation_types/reindex/flyout/progress.tsx b/x-pack/plugins/upgrade_assistant/public/application/components/es_deprecations/deprecation_types/reindex/flyout/progress.tsx
index a58f386216a80..ed5c603deefc1 100644
--- a/x-pack/plugins/upgrade_assistant/public/application/components/es_deprecations/deprecation_types/reindex/flyout/progress.tsx
+++ b/x-pack/plugins/upgrade_assistant/public/application/components/es_deprecations/deprecation_types/reindex/flyout/progress.tsx
@@ -7,7 +7,15 @@
 
 import React, { ReactNode } from 'react';
 
-import { EuiCallOut, EuiFlexGroup, EuiFlexItem, EuiLink, EuiText, EuiTitle } from '@elastic/eui';
+import {
+  EuiCallOut,
+  EuiFlexGroup,
+  EuiFlexItem,
+  EuiLink,
+  EuiText,
+  EuiTitle,
+  EuiCode,
+} from '@elastic/eui';
 import { FormattedMessage } from '@kbn/i18n-react';
 
 import { ReindexStatus, ReindexStep } from '../../../../../../../common/types';
@@ -124,95 +132,168 @@ const ReindexingDocumentsStepTitle: React.FunctionComponent<{
 };
 
 const orderedSteps = Object.values(ReindexStep).sort() as number[];
-const getStepTitle = (step: ReindexStep, inProgress?: boolean): ReactNode => {
+
+const getStepTitle = (
+  step: ReindexStep,
+  meta: ReindexState['meta'],
+  inProgress?: boolean
+): ReactNode => {
   if (step === ReindexStep.readonly) {
     return inProgress ? (
       <FormattedMessage
         id="xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingChecklist.inProgress.readonlyStepTitle"
-        defaultMessage="Setting original index to read-only."
+        defaultMessage="Setting {indexName} index to read-only."
+        values={{
+          indexName: <EuiCode>{meta.indexName}</EuiCode>,
+        }}
       />
     ) : (
       <FormattedMessage
         id="xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingChecklist.readonlyStepTitle"
-        defaultMessage="Set original index to read-only."
+        defaultMessage="Set {indexName} index to read-only."
+        values={{
+          indexName: <EuiCode>{meta.indexName}</EuiCode>,
+        }}
       />
     );
   }
+
   if (step === ReindexStep.newIndexCreated) {
     return inProgress ? (
       <FormattedMessage
         id="xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingChecklist.inProgress.createIndexStepTitle"
-        defaultMessage="Creating new index."
+        defaultMessage="Creating {reindexName} index."
+        values={{
+          reindexName: <EuiCode>{meta.reindexName}</EuiCode>,
+        }}
       />
     ) : (
       <FormattedMessage
         id="xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingChecklist.createIndexStepTitle"
-        defaultMessage="Create new index."
+        defaultMessage="Create {reindexName} index."
+        values={{
+          reindexName: <EuiCode>{meta.reindexName}</EuiCode>,
+        }}
       />
     );
   }
+
   if (step === ReindexStep.aliasCreated) {
     return inProgress ? (
       <FormattedMessage
-        id="xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingChecklist.inProgress.aliasSwapStepTitle"
-        defaultMessage="Swapping original index with alias."
+        id="xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingChecklist.inProgress.aliasCreatedStepTitle"
+        defaultMessage="Creating {indexName} alias for {reindexName} index."
+        values={{
+          indexName: <EuiCode>{meta.indexName}</EuiCode>,
+          reindexName: <EuiCode>{meta.reindexName}</EuiCode>,
+        }}
+      />
+    ) : (
+      <FormattedMessage
+        id="xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingChecklist.aliasCreatedStepTitle"
+        defaultMessage="Create {indexName} alias for {reindexName} index."
+        values={{
+          indexName: <EuiCode>{meta.indexName}</EuiCode>,
+          reindexName: <EuiCode>{meta.reindexName}</EuiCode>,
+        }}
+      />
+    );
+  }
+
+  if (step === ReindexStep.originalIndexDeleted) {
+    return inProgress ? (
+      <FormattedMessage
+        id="xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingChecklist.inProgress.originalIndexDeletedStepTitle"
+        defaultMessage="Deleting original {indexName} index."
+        values={{
+          indexName: <EuiCode>{meta.indexName}</EuiCode>,
+        }}
+      />
+    ) : (
+      <FormattedMessage
+        id="xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingChecklist.originalIndexDeletedStepTitle"
+        defaultMessage="Delete original {indexName} index."
+        values={{
+          indexName: <EuiCode>{meta.indexName}</EuiCode>,
+        }}
+      />
+    );
+  }
+
+  if (step === ReindexStep.existingAliasesUpdated) {
+    return inProgress ? (
+      <FormattedMessage
+        id="xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingChecklist.inProgress.aliasesUpdatedStepTitle"
+        defaultMessage="Updating {existingAliases} aliases to point to {reindexName} index."
+        values={{
+          existingAliases: <EuiCode>{`[${meta.aliases.join(',')}]`}</EuiCode>,
+          reindexName: <EuiCode>{meta.reindexName}</EuiCode>,
+        }}
       />
     ) : (
       <FormattedMessage
-        id="xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingChecklist.aliasSwapStepTitle"
-        defaultMessage="Swap original index with alias."
+        id="xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingChecklist.aliasesUpdatedStepTitle"
+        defaultMessage="Update {existingAliases} aliases to point to {reindexName} index."
+        values={{
+          existingAliases: <EuiCode>{`[${meta.aliases.join(',')}]`}</EuiCode>,
+          reindexName: <EuiCode>{meta.reindexName}</EuiCode>,
+        }}
       />
     );
   }
 };
 
+interface Props {
+  reindexState: ReindexState;
+  cancelReindex: () => void;
+}
+
 /**
  * Displays a list of steps in the reindex operation, the current status, a progress bar,
  * and any error messages that are encountered.
  */
-export const ReindexProgress: React.FunctionComponent<{
-  reindexState: ReindexState;
-  cancelReindex: () => void;
-}> = (props) => {
+export const ReindexProgress: React.FunctionComponent<Props> = (props) => {
   const {
     errorMessage,
     lastCompletedStep = -1,
     status,
     reindexTaskPercComplete,
+    meta,
   } = props.reindexState;
+
   const getProgressStep = (thisStep: ReindexStep): StepProgressStep => {
     const previousStep = orderedSteps[orderedSteps.indexOf(thisStep) - 1];
 
     if (status === ReindexStatus.failed && lastCompletedStep === previousStep) {
       return {
-        title: getStepTitle(thisStep),
+        title: getStepTitle(thisStep, meta),
         status: 'failed',
         children: <ErrorCallout {...{ errorMessage }} />,
       };
     } else if (status === ReindexStatus.paused && lastCompletedStep === previousStep) {
       return {
-        title: getStepTitle(thisStep),
+        title: getStepTitle(thisStep, meta),
         status: 'paused',
         children: <PausedCallout />,
       };
     } else if (status === ReindexStatus.cancelled && lastCompletedStep === previousStep) {
       return {
-        title: getStepTitle(thisStep),
+        title: getStepTitle(thisStep, meta),
         status: 'cancelled',
       };
     } else if (status === undefined || lastCompletedStep < previousStep) {
       return {
-        title: getStepTitle(thisStep),
+        title: getStepTitle(thisStep, meta),
         status: 'incomplete',
       };
     } else if (lastCompletedStep === previousStep) {
       return {
-        title: getStepTitle(thisStep, true),
+        title: getStepTitle(thisStep, meta, true),
         status: 'inProgress',
       };
     } else {
       return {
-        title: getStepTitle(thisStep),
+        title: getStepTitle(thisStep, meta),
         status: 'complete',
       };
     }
@@ -259,8 +340,15 @@ export const ReindexProgress: React.FunctionComponent<{
     getProgressStep(ReindexStep.newIndexCreated),
     reindexingDocsStep,
     getProgressStep(ReindexStep.aliasCreated),
+    getProgressStep(ReindexStep.originalIndexDeleted),
   ];
 
+  const hasExistingAliases = meta.aliases.length > 0;
+
+  if (hasExistingAliases) {
+    steps.push(getProgressStep(ReindexStep.existingAliasesUpdated));
+  }
+
   return (
     <>
       <EuiTitle size="xs" data-test-subj="reindexChecklistTitle">
@@ -270,7 +358,11 @@ export const ReindexProgress: React.FunctionComponent<{
               id="xpack.upgradeAssistant.checkupTab.reindexing.flyout.checklistStep.reindexingInProgressTitle"
               defaultMessage="Reindexing in progress… {percents}"
               values={{
-                percents: getReindexProgressLabel(reindexTaskPercComplete, lastCompletedStep),
+                percents: getReindexProgressLabel(
+                  reindexTaskPercComplete,
+                  lastCompletedStep,
+                  hasExistingAliases
+                ),
               }}
             />
           ) : (
diff --git a/x-pack/plugins/upgrade_assistant/public/application/components/es_deprecations/deprecation_types/reindex/flyout/warning_step.test.tsx b/x-pack/plugins/upgrade_assistant/public/application/components/es_deprecations/deprecation_types/reindex/flyout/warning_step.test.tsx
index 4eac1ec739cfc..bc944f7773ac7 100644
--- a/x-pack/plugins/upgrade_assistant/public/application/components/es_deprecations/deprecation_types/reindex/flyout/warning_step.test.tsx
+++ b/x-pack/plugins/upgrade_assistant/public/application/components/es_deprecations/deprecation_types/reindex/flyout/warning_step.test.tsx
@@ -40,6 +40,11 @@ describe('WarningsFlyoutStep', () => {
     warnings: [] as ReindexWarning[],
     hideWarningsStep: jest.fn(),
     continueReindex: jest.fn(),
+    meta: {
+      indexName: 'foo',
+      reindexName: 'reindexed-foo',
+      aliases: [],
+    },
   };
 
   it('renders', () => {
diff --git a/x-pack/plugins/upgrade_assistant/public/application/components/es_deprecations/deprecation_types/reindex/flyout/warning_step_checkbox.tsx b/x-pack/plugins/upgrade_assistant/public/application/components/es_deprecations/deprecation_types/reindex/flyout/warning_step_checkbox.tsx
index abc7e513f785f..39b3a722055f8 100644
--- a/x-pack/plugins/upgrade_assistant/public/application/components/es_deprecations/deprecation_types/reindex/flyout/warning_step_checkbox.tsx
+++ b/x-pack/plugins/upgrade_assistant/public/application/components/es_deprecations/deprecation_types/reindex/flyout/warning_step_checkbox.tsx
@@ -33,7 +33,7 @@ const WarningCheckbox: React.FunctionComponent<{
   warningId: string;
   label: React.ReactNode;
   description: React.ReactNode;
-  documentationUrl: string;
+  documentationUrl?: string;
   onChange: (event: React.ChangeEvent<HTMLInputElement>) => void;
 }> = ({ isChecked, warningId, label, onChange, description, documentationUrl }) => (
   <>
@@ -47,20 +47,22 @@ const WarningCheckbox: React.FunctionComponent<{
             onChange={onChange}
           />
         </EuiFlexItem>
-        <EuiFlexItem grow={false}>
-          <EuiLink href={documentationUrl} target="_blank" external={false}>
-            <EuiIconTip
-              content={
-                <FormattedMessage
-                  id="xpack.upgradeAssistant.checkupTab.reindexing.flyout.warningsStep.documentationLinkLabel"
-                  defaultMessage="Documentation"
-                />
-              }
-              position="right"
-              type="help"
-            />
-          </EuiLink>
-        </EuiFlexItem>
+        {documentationUrl !== undefined && (
+          <EuiFlexItem grow={false}>
+            <EuiLink href={documentationUrl} target="_blank" external={false}>
+              <EuiIconTip
+                content={
+                  <FormattedMessage
+                    id="xpack.upgradeAssistant.checkupTab.reindexing.flyout.warningsStep.documentationLinkLabel"
+                    defaultMessage="Documentation"
+                  />
+                }
+                position="right"
+                type="help"
+              />
+            </EuiLink>
+          </EuiFlexItem>
+        )}
       </EuiFlexGroup>
 
       <EuiSpacer size="xs" />
@@ -158,3 +160,35 @@ export const DeprecatedSettingWarningCheckbox: React.FunctionComponent<WarningCh
     />
   );
 };
+
+export const ReplaceIndexWithAliasWarningCheckbox: React.FunctionComponent<
+  WarningCheckboxProps
+> = ({ isChecked, onChange, docLinks, id, meta }) => {
+  return (
+    <WarningCheckbox
+      isChecked={isChecked}
+      onChange={onChange}
+      warningId={id}
+      label={
+        <FormattedMessage
+          id="xpack.upgradeAssistant.checkupTab.reindexing.flyout.warningsStep.replaceIndexWithAliasWarningTitle"
+          defaultMessage="Replace {indexName} index with {reindexName} index and create {indexName} index alias"
+          values={{
+            indexName: <EuiCode>{meta?.indexName}</EuiCode>,
+            reindexName: <EuiCode>{meta?.reindexName}</EuiCode>,
+          }}
+        />
+      }
+      description={
+        <FormattedMessage
+          id="xpack.upgradeAssistant.checkupTab.reindexing.flyout.warningsStep.replaceIndexWithAliasWarningDetail"
+          defaultMessage="You can search {indexName} as before. To delete the data you'll have to delete {reindexName}"
+          values={{
+            indexName: <EuiCode>{meta?.indexName}</EuiCode>,
+            reindexName: <EuiCode>{meta?.reindexName}</EuiCode>,
+          }}
+        />
+      }
+    />
+  );
+};
diff --git a/x-pack/plugins/upgrade_assistant/public/application/components/es_deprecations/deprecation_types/reindex/flyout/warnings_step.tsx b/x-pack/plugins/upgrade_assistant/public/application/components/es_deprecations/deprecation_types/reindex/flyout/warnings_step.tsx
index 09cc8f103709a..97760b98e61ed 100644
--- a/x-pack/plugins/upgrade_assistant/public/application/components/es_deprecations/deprecation_types/reindex/flyout/warnings_step.tsx
+++ b/x-pack/plugins/upgrade_assistant/public/application/components/es_deprecations/deprecation_types/reindex/flyout/warnings_step.tsx
@@ -20,11 +20,16 @@ import {
 } from '@elastic/eui';
 import { FormattedMessage } from '@kbn/i18n-react';
 
-import { ReindexWarning, ReindexWarningTypes } from '../../../../../../../common/types';
+import {
+  ReindexWarning,
+  ReindexWarningTypes,
+  ReindexStatusResponse,
+} from '../../../../../../../common/types';
 import { useAppContext } from '../../../../../app_context';
 import {
   CustomTypeNameWarningCheckbox,
   DeprecatedSettingWarningCheckbox,
+  ReplaceIndexWithAliasWarningCheckbox,
   WarningCheckboxProps,
 } from './warning_step_checkbox';
 
@@ -37,6 +42,7 @@ const warningToComponentMap: {
 } = {
   customTypeName: CustomTypeNameWarningCheckbox,
   indexSetting: DeprecatedSettingWarningCheckbox,
+  replaceIndexWithAlias: ReplaceIndexWithAliasWarningCheckbox,
 };
 
 export const idForWarning = (id: number) => `reindexWarning-${id}`;
@@ -44,6 +50,7 @@ interface WarningsConfirmationFlyoutProps {
   hideWarningsStep: () => void;
   continueReindex: () => void;
   warnings: ReindexWarning[];
+  meta: ReindexStatusResponse['meta'];
 }
 
 /**
@@ -54,6 +61,7 @@ export const WarningsFlyoutStep: React.FunctionComponent<WarningsConfirmationFly
   warnings,
   hideWarningsStep,
   continueReindex,
+  meta,
 }) => {
   const {
     services: {
@@ -124,7 +132,7 @@ export const WarningsFlyoutStep: React.FunctionComponent<WarningsConfirmationFly
                   onChange={onChange}
                   docLinks={links}
                   id={idForWarning(index)}
-                  meta={warning.meta}
+                  meta={{ ...meta, ...warning.meta }}
                 />
               );
             })}
diff --git a/x-pack/plugins/upgrade_assistant/public/application/components/es_deprecations/deprecation_types/reindex/resolution_table_cell.tsx b/x-pack/plugins/upgrade_assistant/public/application/components/es_deprecations/deprecation_types/reindex/resolution_table_cell.tsx
index b181e666c17e2..68a754875a737 100644
--- a/x-pack/plugins/upgrade_assistant/public/application/components/es_deprecations/deprecation_types/reindex/resolution_table_cell.tsx
+++ b/x-pack/plugins/upgrade_assistant/public/application/components/es_deprecations/deprecation_types/reindex/resolution_table_cell.tsx
@@ -78,6 +78,7 @@ const i18nTexts = {
 
 export const ReindexResolutionCell: React.FunctionComponent = () => {
   const { reindexState } = useReindexContext();
+  const hasExistingAliases = reindexState.meta.aliases.length > 0;
 
   if (reindexState.loadingState === LoadingState.Loading) {
     return (
@@ -104,7 +105,8 @@ export const ReindexResolutionCell: React.FunctionComponent = () => {
               {i18nTexts.reindexInProgressText}{' '}
               {getReindexProgressLabel(
                 reindexState.reindexTaskPercComplete,
-                reindexState.lastCompletedStep
+                reindexState.lastCompletedStep,
+                hasExistingAliases
               )}
             </EuiText>
           </EuiFlexItem>
diff --git a/x-pack/plugins/upgrade_assistant/public/application/components/es_deprecations/deprecation_types/reindex/use_reindex_state.tsx b/x-pack/plugins/upgrade_assistant/public/application/components/es_deprecations/deprecation_types/reindex/use_reindex_state.tsx
index e3a747e6615b8..9c1e5b932efdd 100644
--- a/x-pack/plugins/upgrade_assistant/public/application/components/es_deprecations/deprecation_types/reindex/use_reindex_state.tsx
+++ b/x-pack/plugins/upgrade_assistant/public/application/components/es_deprecations/deprecation_types/reindex/use_reindex_state.tsx
@@ -8,7 +8,7 @@
 import { useRef, useCallback, useState, useEffect } from 'react';
 
 import {
-  ReindexOperation,
+  ReindexStatusResponse,
   ReindexStatus,
   ReindexStep,
   ReindexWarning,
@@ -27,20 +27,26 @@ export interface ReindexState {
   errorMessage: string | null;
   reindexWarnings?: ReindexWarning[];
   hasRequiredPrivileges?: boolean;
-}
-
-interface StatusResponse {
-  warnings?: ReindexWarning[];
-  reindexOp?: ReindexOperation;
-  hasRequiredPrivileges?: boolean;
+  meta: {
+    indexName: string;
+    reindexName: string;
+    aliases: string[];
+  };
 }
 
 const getReindexState = (
   reindexState: ReindexState,
-  { reindexOp, warnings, hasRequiredPrivileges }: StatusResponse
+  { reindexOp, warnings, hasRequiredPrivileges, meta: updatedMeta }: ReindexStatusResponse
 ) => {
+  const meta = { ...(updatedMeta ?? reindexState.meta) };
+  // Once we have received an array of existing aliases, we won't update the meta value anymore because
+  // when we'll delete the original alias during the reindex process there won't be any aliases pointing
+  // to it anymore and the last reindex step (Update existing aliases) would be suddenly removed.
+  const aliases =
+    reindexState.meta.aliases.length > 0 ? reindexState.meta.aliases : updatedMeta.aliases;
   const newReindexState = {
     ...reindexState,
+    meta: { ...meta, aliases },
     loadingState: LoadingState.Success,
   };
 
@@ -54,7 +60,23 @@ const getReindexState = (
 
   if (reindexOp) {
     // Prevent the UI flickering back to inProgress after cancelling
-    newReindexState.lastCompletedStep = reindexOp.lastCompletedStep;
+
+    let updateLastCompletedStep = true;
+    if (
+      reindexOp.lastCompletedStep === ReindexStep.aliasCreated &&
+      reindexOp.status !== ReindexStatus.completed
+    ) {
+      // "ReindexStep.aliasCreated" is the last step coming from the server
+      // There is a delay between the moment the server returns that the "lastCompletedStep"
+      // is "aliasCreated" and when the server marks reindexing as "completed".
+      // We will correct this timing error by only marking the "aliasCreated" step as done
+      // when the reindex status is "completed".
+      updateLastCompletedStep = false;
+    }
+
+    if (updateLastCompletedStep) {
+      newReindexState.lastCompletedStep = reindexOp.lastCompletedStep;
+    }
     newReindexState.status = reindexOp.status;
     newReindexState.reindexTaskPercComplete = reindexOp.reindexTaskPercComplete;
     newReindexState.errorMessage = reindexOp.errorMessage;
@@ -74,6 +96,11 @@ const getReindexState = (
       reindexOp.status === ReindexStatus.inProgress
     ) {
       newReindexState.cancelLoadingState = CancelLoadingState.Loading;
+    } else if (newReindexState.status === ReindexStatus.completed) {
+      // The Elasticsearch reindex is complete. We will add one or two (depending if there are
+      // existing aliases that need to be updated) "fake" steps only for the UI.
+      // This will help our users understand what actually happened in the last step.
+      newReindexState.status = ReindexStatus.inProgress;
     }
   }
 
@@ -85,6 +112,11 @@ export const useReindexStatus = ({ indexName, api }: { indexName: string; api: A
     loadingState: LoadingState.Loading,
     errorMessage: null,
     reindexTaskPercComplete: null,
+    meta: {
+      indexName,
+      reindexName: '', // will be known after fetching the reindexStatus
+      aliases: [], // will be known after fetching the reindexStatus
+    },
   });
 
   const pollIntervalIdRef = useRef<ReturnType<typeof setTimeout> | null>(null);
@@ -97,6 +129,52 @@ export const useReindexStatus = ({ indexName, api }: { indexName: string; api: A
     }
   }, []);
 
+  /**
+   * When the server says that reindexing is complete we will fake
+   * one (or two in case there are existing aliases to update) extra steps in the UI
+   */
+  const simulateExtraSteps = useCallback(() => {
+    const delay = 1000;
+    const hasExistingAliases = reindexState.meta.aliases.length > 0;
+
+    // Mark "update existing aliases" as completed
+    const completeUpdateExistingAliasesStep = () => {
+      if (!isMounted.current) {
+        return;
+      }
+
+      setReindexState((prevValue: ReindexState) => {
+        return {
+          ...prevValue,
+          status: ReindexStatus.completed,
+          lastCompletedStep: ReindexStep.existingAliasesUpdated,
+        };
+      });
+    };
+
+    // Mark "original index deleted" as completed
+    const completeDeleteOriginalIndexStep = () => {
+      if (!isMounted.current) {
+        return;
+      }
+
+      setReindexState((prevValue: ReindexState) => {
+        return {
+          ...prevValue,
+          status: hasExistingAliases ? ReindexStatus.inProgress : ReindexStatus.completed,
+          lastCompletedStep: ReindexStep.originalIndexDeleted,
+        };
+      });
+
+      if (hasExistingAliases) {
+        // Still one step to go!
+        setTimeout(completeUpdateExistingAliasesStep, delay);
+      }
+    };
+
+    setTimeout(completeDeleteOriginalIndexStep, delay);
+  }, [reindexState.meta.aliases.length]);
+
   const updateStatus = useCallback(async () => {
     clearPollInterval();
 
@@ -114,15 +192,21 @@ export const useReindexStatus = ({ indexName, api }: { indexName: string; api: A
       return;
     }
 
+    if (data === null) {
+      return;
+    }
+
     setReindexState((prevValue: ReindexState) => {
       return getReindexState(prevValue, data);
     });
 
-    // Only keep polling if it exists and is in progress.
     if (data.reindexOp && data.reindexOp.status === ReindexStatus.inProgress) {
+      // Only keep polling if it exists and is in progress.
       pollIntervalIdRef.current = setTimeout(updateStatus, POLL_INTERVAL);
+    } else if (data.reindexOp && data.reindexOp.status === ReindexStatus.completed) {
+      simulateExtraSteps();
     }
-  }, [clearPollInterval, api, indexName]);
+  }, [clearPollInterval, api, indexName, simulateExtraSteps]);
 
   const startReindex = useCallback(async () => {
     setReindexState((prevValue: ReindexState) => {
@@ -153,7 +237,7 @@ export const useReindexStatus = ({ indexName, api }: { indexName: string; api: A
     }
 
     setReindexState((prevValue: ReindexState) => {
-      return getReindexState(prevValue, { reindexOp });
+      return getReindexState(prevValue, { reindexOp, meta: prevValue.meta });
     });
     updateStatus();
   }, [api, indexName, updateStatus]);
@@ -179,6 +263,10 @@ export const useReindexStatus = ({ indexName, api }: { indexName: string; api: A
     }
   }, [api, indexName]);
 
+  useEffect(() => {
+    updateStatus();
+  }, [updateStatus]);
+
   useEffect(() => {
     isMounted.current = true;
 
diff --git a/x-pack/plugins/upgrade_assistant/public/application/lib/api.ts b/x-pack/plugins/upgrade_assistant/public/application/lib/api.ts
index 5dcd49fa17958..f3c5680b56e20 100644
--- a/x-pack/plugins/upgrade_assistant/public/application/lib/api.ts
+++ b/x-pack/plugins/upgrade_assistant/public/application/lib/api.ts
@@ -13,6 +13,7 @@ import {
   ClusterUpgradeState,
   ResponseError,
   SystemIndicesMigrationStatus,
+  ReindexStatusResponse,
 } from '../../../common/types';
 import {
   API_BASE_PATH,
@@ -209,7 +210,7 @@ export class ApiService {
   }
 
   public async getReindexStatus(indexName: string) {
-    return await this.sendRequest({
+    return await this.sendRequest<ReindexStatusResponse>({
       path: `${API_BASE_PATH}/reindex/${indexName}`,
       method: 'get',
     });
diff --git a/x-pack/plugins/upgrade_assistant/public/application/lib/utils.test.ts b/x-pack/plugins/upgrade_assistant/public/application/lib/utils.test.ts
index 37392c832ecf5..b8eb245b631f6 100644
--- a/x-pack/plugins/upgrade_assistant/public/application/lib/utils.test.ts
+++ b/x-pack/plugins/upgrade_assistant/public/application/lib/utils.test.ts
@@ -54,15 +54,53 @@ describe('getReindexProgressLabel', () => {
     expect(getReindexProgressLabel(0, ReindexStep.reindexStarted)).toBe('10%');
   });
 
-  it('returns 53% when the reindexing documents progress is 0.5', () => {
-    expect(getReindexProgressLabel(0.5, ReindexStep.reindexStarted)).toBe('53%');
+  it('returns 50% when the reindexing documents progress is 0.5', () => {
+    expect(getReindexProgressLabel(0.5, ReindexStep.reindexStarted)).toBe('50%');
   });
 
-  it('returns 95% when the reindexing documents progress is 1', () => {
-    expect(getReindexProgressLabel(1, ReindexStep.reindexStarted)).toBe('95%');
+  it('returns 90% when the reindexing documents progress is 1', () => {
+    expect(getReindexProgressLabel(1, ReindexStep.reindexStarted)).toBe('90%');
   });
 
-  it('returns 100% when alias has been switched', () => {
-    expect(getReindexProgressLabel(null, ReindexStep.aliasCreated)).toBe('100%');
+  it('returns 95% when alias has been created', () => {
+    expect(getReindexProgressLabel(null, ReindexStep.aliasCreated)).toBe('95%');
+  });
+
+  it('returns 100% when original index has been deleted', () => {
+    expect(getReindexProgressLabel(null, ReindexStep.originalIndexDeleted)).toBe('100%');
+  });
+
+  describe('when there are existing aliases', () => {
+    const withExistingAliases = true;
+
+    it('returns 48% when the reindexing documents progress is 0.5', () => {
+      expect(getReindexProgressLabel(0.5, ReindexStep.reindexStarted, withExistingAliases)).toBe(
+        '48%'
+      );
+    });
+
+    it('returns 85% when the reindexing documents progress is 1', () => {
+      expect(getReindexProgressLabel(1, ReindexStep.reindexStarted, withExistingAliases)).toBe(
+        '85%'
+      );
+    });
+
+    it('returns 90% when alias has been created', () => {
+      expect(getReindexProgressLabel(null, ReindexStep.aliasCreated, withExistingAliases)).toBe(
+        '90%'
+      );
+    });
+
+    it('returns 95% when original index has been deleted', () => {
+      expect(
+        getReindexProgressLabel(null, ReindexStep.originalIndexDeleted, withExistingAliases)
+      ).toBe('95%');
+    });
+
+    it('returns 100% when original index has been deleted', () => {
+      expect(
+        getReindexProgressLabel(null, ReindexStep.existingAliasesUpdated, withExistingAliases)
+      ).toBe('100%');
+    });
   });
 });
diff --git a/x-pack/plugins/upgrade_assistant/public/application/lib/utils.ts b/x-pack/plugins/upgrade_assistant/public/application/lib/utils.ts
index bdbc0949e368b..b13b20e7016f9 100644
--- a/x-pack/plugins/upgrade_assistant/public/application/lib/utils.ts
+++ b/x-pack/plugins/upgrade_assistant/public/application/lib/utils.ts
@@ -37,15 +37,17 @@ export const getDeprecationsUpperLimit = (count: number) => {
 };
 
 /*
- * Reindexing task consists of 4 steps: making the index read-only, creating a new index,
- * reindexing documents into the new index and switching alias from the old to the new index.
- * Steps 1, 2 and 4 each contribute 5% to the overall progress.
+ * Reindexing task consists of 5 (or 6) steps: making the index read-only, creating a new index,
+ * reindexing documents into the new index, creating an alias to point to the newly created index,
+ * delete the original index, (optionally) update existing aliases to point to the new index.
+ * Steps 1, 2 and 4, 5 & 6 each contribute 5% to the overall progress.
  * Step 3 (reindexing documents) can take a long time for large indices and its progress is calculated
- * between 10% and 95% of the overall progress depending on its completeness percentage.
+ * between 10% and 90% of the overall progress depending on its completeness percentage.
  */
 export const getReindexProgressLabel = (
   reindexTaskPercComplete: number | null,
-  lastCompletedStep: ReindexStep | undefined
+  lastCompletedStep: ReindexStep | undefined,
+  hasExistingAliases: boolean = false
 ): string => {
   let percentsComplete = 0;
   switch (lastCompletedStep) {
@@ -66,16 +68,28 @@ export const getReindexProgressLabel = (
     case ReindexStep.reindexStarted: {
       // step 3 started, 10-95% progress depending on progress of reindexing documents in ES
       percentsComplete =
-        reindexTaskPercComplete !== null ? 10 + Math.round(reindexTaskPercComplete * 85) : 10;
+        reindexTaskPercComplete !== null
+          ? 10 + Math.round(reindexTaskPercComplete * (hasExistingAliases ? 75 : 80))
+          : 10;
       break;
     }
     case ReindexStep.reindexCompleted: {
-      // step 3 completed, only step 4 remaining, 95% progress
-      percentsComplete = 95;
+      // step 3 completed
+      percentsComplete = hasExistingAliases ? 85 : 90;
       break;
     }
     case ReindexStep.aliasCreated: {
-      // step 4 completed, 100% progress
+      // step 4 completed
+      percentsComplete = hasExistingAliases ? 90 : 95;
+      break;
+    }
+    case ReindexStep.originalIndexDeleted: {
+      // step 5 completed
+      percentsComplete = hasExistingAliases ? 95 : 100;
+      break;
+    }
+    case ReindexStep.existingAliasesUpdated: {
+      // step 6 completed, 100% progress
       percentsComplete = 100;
       break;
     }
diff --git a/x-pack/plugins/upgrade_assistant/server/lib/reindexing/index.ts b/x-pack/plugins/upgrade_assistant/server/lib/reindexing/index.ts
index c1ff38b08678f..1ab6a26e90ffb 100644
--- a/x-pack/plugins/upgrade_assistant/server/lib/reindexing/index.ts
+++ b/x-pack/plugins/upgrade_assistant/server/lib/reindexing/index.ts
@@ -7,3 +7,4 @@
 
 export { reindexServiceFactory } from './reindex_service';
 export { ReindexWorker } from './worker';
+export { generateNewIndexName } from './index_settings';
diff --git a/x-pack/plugins/upgrade_assistant/server/lib/reindexing/reindex_service.test.ts b/x-pack/plugins/upgrade_assistant/server/lib/reindexing/reindex_service.test.ts
index b68faf7f75b99..268846a31d2bd 100644
--- a/x-pack/plugins/upgrade_assistant/server/lib/reindexing/reindex_service.test.ts
+++ b/x-pack/plugins/upgrade_assistant/server/lib/reindexing/reindex_service.test.ts
@@ -164,13 +164,17 @@ describe('reindexService', () => {
       });
 
       const reindexWarnings = await service.detectReindexWarnings(indexName);
-      expect(reindexWarnings).toEqual([]);
+      expect(reindexWarnings).toEqual([
+        {
+          warningType: 'replaceIndexWithAlias',
+        },
+      ]);
     });
 
     it('returns null if index does not exist', async () => {
       actions.getFlatSettings.mockResolvedValueOnce(null);
       const reindexWarnings = await service.detectReindexWarnings('myIndex');
-      expect(reindexWarnings).toBeNull();
+      expect(reindexWarnings).toBeUndefined();
     });
   });
 
diff --git a/x-pack/plugins/upgrade_assistant/server/lib/reindexing/reindex_service.ts b/x-pack/plugins/upgrade_assistant/server/lib/reindexing/reindex_service.ts
index f9db1692ab1b7..db427161f50d3 100644
--- a/x-pack/plugins/upgrade_assistant/server/lib/reindexing/reindex_service.ts
+++ b/x-pack/plugins/upgrade_assistant/server/lib/reindexing/reindex_service.ts
@@ -42,7 +42,7 @@ export interface ReindexService {
    * Resolves to null if index does not exist.
    * @param indexName
    */
-  detectReindexWarnings(indexName: string): Promise<ReindexWarning[] | null>;
+  detectReindexWarnings(indexName: string): Promise<ReindexWarning[] | undefined>;
 
   /**
    * Creates a new reindex operation for a given index.
@@ -115,6 +115,8 @@ export interface ReindexService {
    * @param indexName
    */
   cancelReindexing(indexName: string): Promise<ReindexSavedObject>;
+
+  getIndexAliases(indexName: string): any;
 }
 
 export const reindexServiceFactory = (
@@ -311,6 +313,14 @@ export const reindexServiceFactory = (
     return reindexOp;
   };
 
+  const getIndexAliases = async (indexName: string) => {
+    const { body: response } = await esClient.indices.getAlias({
+      index: indexName,
+    });
+
+    return response[indexName]?.aliases ?? {};
+  };
+
   /**
    * Creates an alias that points the old index to the new index, deletes the old index.
    * @param reindexOp
@@ -318,11 +328,7 @@ export const reindexServiceFactory = (
   const switchAlias = async (reindexOp: ReindexSavedObject) => {
     const { indexName, newIndexName, reindexOptions } = reindexOp.attributes;
 
-    const { body: response } = await esClient.indices.getAlias({
-      index: indexName,
-    });
-
-    const existingAliases = response[indexName].aliases;
+    const existingAliases = await getIndexAliases(indexName);
 
     const extraAliases = Object.keys(existingAliases).map((aliasName) => ({
       add: { index: newIndexName, alias: aliasName, ...existingAliases[aliasName] },
@@ -402,12 +408,21 @@ export const reindexServiceFactory = (
       return resp.has_all_requested;
     },
 
-    async detectReindexWarnings(indexName: string) {
+    async detectReindexWarnings(indexName: string): Promise<ReindexWarning[] | undefined> {
       const flatSettings = await actions.getFlatSettings(indexName);
+
       if (!flatSettings) {
-        return null;
+        return undefined;
       } else {
-        return getReindexWarnings(flatSettings);
+        return [
+          // By default all reindexing operations will replace an index with an alias (with the same name)
+          // pointing to a newly created "reindexed" index. This is destructive as delete operations originally
+          // done on the index itself will now need to be done to the "reindexed-{indexName}"
+          {
+            warningType: 'replaceIndexWithAlias',
+          },
+          ...getReindexWarnings(flatSettings),
+        ];
       }
     },
 
@@ -602,5 +617,7 @@ export const reindexServiceFactory = (
 
       return reindexOp;
     },
+
+    getIndexAliases,
   };
 };
diff --git a/x-pack/plugins/upgrade_assistant/server/routes/reindex_indices/reindex_indices.test.ts b/x-pack/plugins/upgrade_assistant/server/routes/reindex_indices/reindex_indices.test.ts
index 9fcff5748a987..38a78f15f2b50 100644
--- a/x-pack/plugins/upgrade_assistant/server/routes/reindex_indices/reindex_indices.test.ts
+++ b/x-pack/plugins/upgrade_assistant/server/routes/reindex_indices/reindex_indices.test.ts
@@ -23,6 +23,7 @@ const mockReindexService = {
   processNextStep: jest.fn(),
   resumeReindexOperation: jest.fn(),
   cancelReindexing: jest.fn(),
+  getIndexAliases: jest.fn().mockResolvedValue({}),
 };
 jest.mock('../../lib/es_version_precheck', () => ({
   versionCheckHandlerWrapper: (a: any) => a,
@@ -31,6 +32,7 @@ jest.mock('../../lib/es_version_precheck', () => ({
 jest.mock('../../lib/reindexing', () => {
   return {
     reindexServiceFactory: () => mockReindexService,
+    generateNewIndexName: () => 'reindexed-foo',
   };
 });
 
@@ -159,7 +161,7 @@ describe('reindex API', () => {
 
       expect(resp.status).toEqual(200);
       const data = resp.payload;
-      expect(data.reindexOp).toBeNull();
+      expect(data.reindexOp).toBeUndefined();
       expect(data.warnings).toBeNull();
     });
   });
diff --git a/x-pack/plugins/upgrade_assistant/server/routes/reindex_indices/reindex_indices.ts b/x-pack/plugins/upgrade_assistant/server/routes/reindex_indices/reindex_indices.ts
index 30f7c77cf73ab..d5776cb161b4d 100644
--- a/x-pack/plugins/upgrade_assistant/server/routes/reindex_indices/reindex_indices.ts
+++ b/x-pack/plugins/upgrade_assistant/server/routes/reindex_indices/reindex_indices.ts
@@ -9,8 +9,9 @@ import { schema } from '@kbn/config-schema';
 import { errors } from '@elastic/elasticsearch';
 
 import { API_BASE_PATH } from '../../../common/constants';
+import type { ReindexStatusResponse } from '../../../common/types';
 import { versionCheckHandlerWrapper } from '../../lib/es_version_precheck';
-import { reindexServiceFactory, ReindexWorker } from '../../lib/reindexing';
+import { reindexServiceFactory, ReindexWorker, generateNewIndexName } from '../../lib/reindexing';
 import { reindexActionsFactory } from '../../lib/reindexing/reindex_actions';
 import { RouteDependencies } from '../../types';
 import { mapAnyErrorToKibanaHttpResponse } from './map_any_error_to_kibana_http_response';
@@ -114,12 +115,21 @@ export function registerReindexIndicesRoutes(
             ? await reindexService.detectReindexWarnings(indexName)
             : [];
 
-          return response.ok({
-            body: {
-              reindexOp: reindexOp ? reindexOp.attributes : null,
-              warnings,
-              hasRequiredPrivileges,
+          const indexAliases = await reindexService.getIndexAliases(indexName);
+
+          const body: ReindexStatusResponse = {
+            reindexOp: reindexOp ? reindexOp.attributes : undefined,
+            warnings,
+            hasRequiredPrivileges,
+            meta: {
+              indexName,
+              reindexName: generateNewIndexName(indexName),
+              aliases: Object.keys(indexAliases),
             },
+          };
+
+          return response.ok({
+            body,
           });
         } catch (error) {
           if (error instanceof errors.ResponseError) {
diff --git a/x-pack/test/upgrade_assistant_integration/upgrade_assistant/reindexing.js b/x-pack/test/upgrade_assistant_integration/upgrade_assistant/reindexing.js
index d52f407e8483f..af2393d7b00d1 100644
--- a/x-pack/test/upgrade_assistant_integration/upgrade_assistant/reindexing.js
+++ b/x-pack/test/upgrade_assistant_integration/upgrade_assistant/reindexing.js
@@ -123,7 +123,10 @@ export default function ({ getService }) {
 
     it('shows no warnings', async () => {
       const resp = await supertest.get(`/api/upgrade_assistant/reindex/7.0-data`);
-      expect(resp.body.warnings.length).to.be(0);
+      // By default all reindexing operations will replace an index with an alias (with the same name)
+      // pointing to a newly created "reindexed" index.
+      expect(resp.body.warnings.length).to.be(1);
+      expect(resp.body.warnings[0].warningType).to.be('replaceIndexWithAlias');
     });
 
     it('reindexes old 7.0 index', async () => {