diff --git a/pkg/ua/ua.go b/pkg/ua/ua.go
index e56c8e3..38726ba 100644
--- a/pkg/ua/ua.go
+++ b/pkg/ua/ua.go
@@ -492,7 +492,7 @@ func (ua *UserAgent) RequestWithContext(ctx context.Context, request sip.Request
 			case provisional := <-provisionals:
 				callID, ok := provisional.CallID()
 				if ok {
-					branchID := utils.GetBranchID(provisional.(sip.Request))
+					branchID := utils.GetBranchID(provisional)
 					if v, found := ua.iss.Load(NewSessionKey(*callID, branchID)); found {
 						is := v.(*session.Session)
 						is.StoreResponse(provisional)
@@ -527,7 +527,7 @@ func (ua *UserAgent) RequestWithContext(ctx context.Context, request sip.Request
 			case response := <-responses:
 				callID, ok := response.CallID()
 				if ok {
-					branchID := utils.GetBranchID(response.(sip.Request))
+					branchID := utils.GetBranchID(response)
 					if v, found := ua.iss.Load(NewSessionKey(*callID, branchID)); found {
 						if request.IsInvite() {
 							is := v.(*session.Session)
diff --git a/pkg/utils/util.go b/pkg/utils/util.go
index 37aa175..73647c7 100644
--- a/pkg/utils/util.go
+++ b/pkg/utils/util.go
@@ -16,8 +16,8 @@ var (
 	ErrPort       = errors.New("invalid port")
 )
 
-func GetBranchID(request sip.Request) sip.MaybeString {
-	if viaHop, ok := request.ViaHop(); ok {
+func GetBranchID(msg sip.Message) sip.MaybeString {
+	if viaHop, ok := msg.ViaHop(); ok {
 		if branch, ok := viaHop.Params.Get("branch"); ok {
 			return branch
 		}