I used to work on the bigger ones for Hughes Satellite Systems from 2' to 12' in size. If it is currently working where it is at then it can be done with a Smart Phone. A Digital Compass app & Digital Level app and having a TV tuned to the Signal strength screen. I would mark the Elevation, Azimuth & Polarization settings before starting. I loosened up the Polartization and set that back to 0 degrees then get a Compass reading on the arm to the LNB. Also get a Compass reading of where it is pointing. I would look at landmarks (mountains, buildings, power poles..) of where it is pointed from standing directly behind it. Move the dish to the new location, point it with the recorded readings & then set the Polarization back again. As long as the roofs are the same pitch & facing the same way then there shouldn't be too many issues.
I have heard that Directv does this for free if you have been with them for a while but I may be wrong.