1 files changed, 1 insertions, 1 deletions

diff --git a/services/pull/pull.go b/services/pull/pull.go
index 5c7ec91f5d..ce5c4ff22f 100644
--- a/services/pull/pull.go
+++ b/services/pull/pull.go
@@ -120,7 +120,7 @@ func ChangeTargetBranch(pr *models.PullRequest, doer *models.User, targetBranch
 	if pr.Status == models.PullRequestStatusChecking {
 		pr.Status = models.PullRequestStatusMergeable
 	}
-	if err := pr.UpdateCols("status, conflicted_files, base_branch"); err != nil {
+	if err := pr.UpdateColsIfNotMerged("merge_base", "status", "conflicted_files", "base_branch"); err != nil {
 		return err
 	}