NORTON 360 ALL IN ONE SECURITY

Question

BROUGHT TWO COMPUTERS FROM COMET AND WAS GIVEN ONE NORTON 360 LOADED ON TO BOTH PC ONE IS RUNNING FINE THE OTHER AT MY HOME IS TELLING PRODUCT HAS EXSPIRED BROUGHT A NEW PACK FROM COMET BUT NOT ASKING FOR PRODUCT KEY AS IT'S OLD PRODUCT KEY ON MY SYSTEM HOW CAN I CHANGE OLD KEY NUMBER TO THE NEW ONE