diff --git a/entrypoint.sh b/entrypoint.sh
index 6568e5d..6fdd1f0 100755
--- a/entrypoint.sh
+++ b/entrypoint.sh
@@ -1,6 +1,7 @@
 #!/bin/bash -e
 
 API="$GITHUB_SERVER_URL/api/actions_pipeline/_apis/pipelines/workflows/$GITHUB_RUN_ID/artifacts"
+[ -n "$INPUT_RETENTION_DAYS" ] && RETENTION="retentionDays=$INPUT_RETENTION_DAYS"
 CURL=(curl --fail -v -D/dev/stdout
     --header "Authorization: Bearer $ACTIONS_RUNTIME_TOKEN"
     --data '{"Type":"actions_storage","Name":"'"$INPUT_NAME"'"}'
@@ -18,7 +19,7 @@ for artifact in $INPUT_PATH; do
     --header "x-actions-results-md5: $md5" \
     --header "x-tfs-filelength: $content_length" \
     --header "content-range: bytes 0-$((content_length - 1))/$content_length" \
-        "$UPLOAD_URL?retentionDays=$INPUT_RETENTION_DAYS&itemPath=$INPUT_NAME%2F$artifact"
+        "$UPLOAD_URL?$RETENTION&itemPath=$INPUT_NAME%2F$artifact"
   cat resp1.json
   "${CURL[@]}" -XPATCH -oresp2.json "$API&artifactName=$INPUT_NAME"
   cat resp2.json