I tried to migrate a SQL Server database by Export Data-tier Application (.bacpac file) from an Amazon RDS instance to other, but import didn\'t succeed. So now
This is the answer for an old thread but who knows, it might help someone having the same issue.
I run into the same problem, but in my case, my database was in offline mode. If the database is in offline mode, it won't allow you to drop it with the drop command. first, you should bring the database back online by running this sp and then execute the drop table command.
EXEC rdsadmin.dbo.rds_set_database_online databasename