He'll almost certainly simply remove the old cable and attach a new one (terminating where you want it to be) to the dish. All he has to do is to remove the existing clips to the wall (allowing him to release the old cable), unscrew the cable from the LNB in the dish, screw a new cable on (having first terminated a length of cable with the appropriate connector), clip it to the wall, find an entry point into the required room (e.g. by drilling a hole in the wall), feed the new cable through and fit a connection onto the other end. A total amateur could do it in well under an hour; a guy who does it for a living should only take half that time.