update with EO feature

Author: an-emma

articles/stream-analytics/event-hubs-output.md

@@ -1,11 +1,11 @@
 ---
 title: Event Hubs output from Azure Stream Analytics
 description: This article describes how to output data from Azure Stream Analytics to Azure Event Hubs.
-author: enkrumah
-ms.author: ebnkruma
+author: an-emma
+ms.author: raan
 ms.service: stream-analytics
 ms.topic: conceptual
-ms.date: 09/23/2020
+ms.date: 02/27/2023
 ---
 # Event Hubs output from Azure Stream Analytics
 
@@ -57,6 +57,12 @@ The following image is of the expected output message properties inspected in Ev
 
 :::image type="content" source="media/event-hubs-output/custom-properties.png" alt-text="Event custom properties":::
 
+## Exactly Once Delivery
+
+Exactly once delivery is supported in Event Hub output by default. Regardless of your input, Stream Analytics guarantees no data loss or no duplicates in Event Hub output, across user-initiated restarts from last output time, preventing duplicates from being produced. This greatly simplifies the streaming pipeline by not having to monitor, implement, and troubleshoot deduplication logic.
+
+Please note that exactly once delivery is not supported when the partition key is specified.
+
 ## Next steps
 
 * [Use managed identities to access Event Hub from an Azure Stream Analytics job (Preview)](event-hubs-managed-identity.md)