Merge pull request #5910 from haileytap/hailey-upgrade

[Azure Search] Add reliability information to search-how-to-upgrade.md

Author: prmerger-automator[bot]

articles/search/search-how-to-upgrade.md

@@ -8,7 +8,7 @@ ms.author: haileytapia
 ms.service: azure-ai-search
 ms.topic: how-to
 ms.custom: references_regions
-ms.date: 04/29/2025
+ms.date: 07/07/2025
 ---
 
 # Upgrade your Azure AI Search service in the Azure portal
@@ -76,7 +76,9 @@ The date you created your service partially determines its [upgrade eligibility]
 
 ## Upgrade your service
 
-You can’t undo a service upgrade. Before you proceed, make sure that you want to permanently increase the [storage limit](#higher-storage-limits) and [vector index size](#higher-vector-limits) of your search service. We recommend that you test this operation in a nonproduction environment.
+You can't undo a service upgrade. Before you proceed, make sure that you want to permanently increase the [storage limit](#higher-storage-limits) and [vector index size](#higher-vector-limits) of your search service. We recommend that you test this operation in a nonproduction environment.
+
+The availability of your search service during an upgrade depends on how many replicas you've provisioned. With two or more replicas, your service remains available while one replica is updated. For more information, see [Reliability in Azure AI Search](search-reliability.md).
 
 To upgrade your service:
 
@@ -100,9 +102,7 @@ To upgrade your service:
 
 1. Check your notifications to confirm that the operation started.
 
-   The upgrade is an asynchronous operation, so you can continue using your service. Depending on the size of your service, the upgrade can take several hours to complete.
-
-   If the upgrade fails, your service returns to its original state.
+   Depending on the size of your service, this operation can take several hours to complete. If the upgrade fails, your service returns to its original state.
 
 ## Next step