When you specify this option, PGPMenu will print out all the keys that you can choose from. You must then select which key you wish to use, and PGPMenu will sett your UserID to that key. Future PGP executions will use this key.
This option will not change the UserID on your key; it only allows you to select which key you will use, based upon the UserID.
When this finishes, PGPMenu will wait for you to tell it to return to the configuration menu.