Unually you need to gain access the the inside of the dash panel the socket is mounted in, then there's a coller that screws on the back on the socket with 2 legs that go the length of the socket and sit against the back of the dash, unscrew the collar/leg assembly and the socket wll come out the front of the dash (remember to remove the off-set multiplug from the rear of the socket 1st though !
If you are doing a straight swap the easiest way is to remove the wireing plug, then just losen the collar a 1/4 turn and hold if firmly in position, then unscrew the rest of the thread via the socket itself, this makes it MUCH easier to get the new unit in and the thread started.