Migrating an RDS instance from SQL Server Standard Edition to Enterprise Edition

You can upgrade the edition from standard to Enterprise [1], the endpoint of the RDS instance will be changed. This happens because, in order to achieve this edition upgrade, you have to restore from a snapshot - and when you restore from a snapshot you have to specify a different DB instance name, which creates a different endpoint.

However, the workaround for this would be: after you restore from the snapshot, make sure you 100% validate that everything is running the way you want and then delete or rename the previous RDS instance (the Standard one). After you delete or rename, its endpoint will be available to be used again, so you modify the restored instance (the Enterprise one) and change the 'DB name identifier' back to the value you want. This will change its endpoint back to what it was.

In summary, here's what you need to do in order to achieve this:

1 - Create a DB snapshot from your source instance (Standard edition) [2];

2 - Restore from the DB snapshot you just created. On the restore screen, change the 'DB Engine' to Enterprise [3] and give it a temporary name, such as 'restored-db-instance-temp'. Also make sure all the VPC and Security Group settings are set according your needs. 

3 - Once your new instance is created, connect to it and validate that everything is fine;

4 - Delete (or modify the DB instance identifier of [3]) the previous instance (the Standard edition instance);

5 - When step 4 is complete, modify your new instance (Enterprise) to change the 'DB Instance Identifier'. Make sure to apply the changes immediately.

By doing this, your new instance (Enterprise Edition) will now have the same DB instance identifier as the former one, thus having the same endpoint.

Important note: the automatic backups/snapshots from the 'old' instance will not follow the rename and become automatic backups/snapshots on the 'new' instance.

[1] https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_CreateSnapshot.html [2] https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_RestoreFromSnapshot.html#USER_RestoreFromSnapshot.MSSQL [3] Renaming a DB Instance - https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_RenameInstance.html