diff --git a/CHANGELOG.md b/CHANGELOG.md
index aa68140715202..f62388ab00d81 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -46,6 +46,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Change http code on create index API with bad input raising NotXContentException from 500 to 400 ([#4773](https://github.com/opensearch-project/OpenSearch/pull/4773))
 - Change http code for DecommissioningFailedException from 500 to 400 ([#5283](https://github.com/opensearch-project/OpenSearch/pull/5283))
 - Improve summary error message for invalid setting updates ([#4792](https://github.com/opensearch-project/OpenSearch/pull/4792))
+- Changed http code for in-flight search tasks cancelled due to search backpressure from 500 to 429 ([#6634](https://github.com/opensearch-project/OpenSearch/pull/6634))
 
 ### Deprecated