Roll Axis potentiometer question

According the wiring diagram, need to reverse the polarity of the above(as well as pitch motor) .... can follow that doing it with the motor, simply a case of reversing the connections on motors' terminals .... with the potentiometer, have no idea how ??? .... appreciate some help ........

My build dead in the water until i get some help ...... anyone ???

Just swap the two outside wires keeping the central one in place.