Determine where you need to move the new rough-in. Measure and mark the subfloor accordingly to give yourself a guide.
Unscrew the existing flange and use it as a template to draw the circular section to cut out for the new pipe. Create a starter cut with the drill and use the jigsaw to cut out the new rough-in opening. Save the cut-out piece.
Extend the old pipe over to the new rough-in section with a new section of PVC pipe that is the same diameter as the existing pipe. Set the flange in place so that its bottom side sticks through the subfloor beneath.
Use the tape measure, pencil and hacksaw to measure, mark and cut a length of pipe to reach over to the new location of the rough-in. Dry fit everything in place to ensure that it fits before cementing. Attach the new length of PVC pipe to the underside of the rough-in. Use couplers to attach the new piece of PVC pipe to the drain and to the rough-in.
Clean the inside and outside of the pipes with your hand after confirming everything fits together as it should. Prime the outside of the male pieces and the inside of the female pieces with the primer. Apply pipe cement to the same male/female sections of the couplers, and connect all of the couplers together. Screw the rough-in into place in the subfloor.
Cut down a scrap piece of wood that is long enough to fit across the entire hole from the old cut-out and is several inches wide. Use the jigsaw to cut it. Hold the scrap piece in place on the underside of the subfloor, spanning the old cut-out. Sink screws into either side of the cut-out to hold the scrap piece of wood in place. Afterwards, place the new cut-out in place and screw it down into the section of wood spanning the gap. Cover this with your finish floor installation.