No good pictures to help you, if you need them after I describe it I can take some.
You need to go from the front of the connector -the side where there wires aren't. You will need a very thin screwdriver or shim or the proper tool shown below.

Take the screwdriver/tool and place it between the flat portion of the connector and the plastic housing. You are trying to push down a tap this is sticking up on the connector. Once the tap is pushed down, keep the tool in place and pull the wire out the back .
Once the wire is out, lift the little tab back up and insert the wire into the new slot.