That would depend on where it is. If it is in a panel it may be possible to simply elongate the opening and use a plastic plasterboard box to mount the new socket.
We have a 4 plug gang unit plugged into the single socket, for charging devices, radio etc. We don’t have wall room where the socket is to convert it to a double socket.
A day of all things motorhome and campervan. The show is held both in the main indoor arena and across the grounds. Catering, hot drinks and food options are available. Easy access to the site and free parking included. Win one of five pairs of day tickets