Use the point of a spudger to push on alternating sides of the plastic latch on the scroll wheel board connector.

You should feel the latch pop into the unlocked position. Don't push too far, or the latch may come completely off the connector.

Use tweezers to gently pull the cable straight out of its socket.

The cable should come out easily. If you feel any resistance, push the latch out a little more and try again.