Should be fairly straight forward. You will have to open a portion of the the wall and ceiling in the closet to gain access to the wire. The wire most likely passes through the top plate into the valley and then is fed out through the cinder block wall. Remove the button and pull the wire out. Drill a new hole through the top plate in the area you plan to install the button at and pull the wire down into the valley. Use a hammer drill to drill through the masonry at the new location and fish the wire through the hole. A 1/4" hole should suffice. Wire your new button up and install in the new location per manufacture directions. Fill the hole where the wire previously passed through with hydraulic cement (sold in tubs in the masonry aisle of both home depot and lowes). If you cut carefully you should be able to reuse the drywall cut outs. Install nailers as needed, tape, mud, sand, and paint.