This command can be used to play as/switch to another empire. Your starting empire has an ID of 00. This command will cause the empire you switch from to be governed by AI.
play [empire id]
|Empire ID||The ID of the empire you wish to play as. Enter 'x' to continue playing after observing.|
This command will make you switch you to your starting empire (if you had previously switched to another). This is because 00 is always the ID of your starting empire.
This command would make you play as the empire with ID 23