How to delete and update the RDS cluster having RDS instance using CFT?

The situation is I have a RDS cluster running with RDS instance in it. Sometimes when we update the stack for RDS cluster it deletes the physical resource and re creates it. But as the RDS instance is still running inside it the deletion gets failed.

Is there any workaround to update the RDS cluster configuration without deleting it or if its recreating the cluster by deleting it, it should delete the RDS instance first and then delete the RDS cluster.