you dont save under a new name....if you want to save a copy of the original under a new name you can, (I personally dont save a copy of the original, its wrong, I have no use for it anymore, I just keep a printed/pdf copy of it) but the amended return should be the same file and filename as the original one that was Efiled....you'd want that same file name when you transfer the client file to 2021 anyhow.

People that same the newly amended return under a new name seem to have trouble with the program recognizing that the original had been efiled.