Pull the DC-in cable connector out with your fingers. If you aren't able to pull it by the connector, use the point of a spudger to push on alternating sides of the connector to "walk" it out of its socket.

It may take a lot of alternating before the connector comes out. Be patient, and don't pull on the cables.

To reconnect the cable, align the connector and use a spudger or clean fingernail to push it fully into the socket.

Don't push on the cables themselves, or you may damage the connector.