RMS Function Key, deleting of or modification to

I was searching the Forum lately to see if unused Function Keys, such as Gas Pump, could be deleted from the Transaction screen Function Key menu and came across a post that said those keys could not be altered.  However, the RMS User Guide, pages 294 and 295, seems to indicate that the Function Keys can be deleted.

Before I attempt to delete a key, I thought I'd ask the question:  Can you delete the unused Function Keys?

Also, I am interested in changing the Cash Drop Function Key to an Alt Key.  Can this be done?