Originally Posted by
WineCountryUA
Those on awards, if not GS or primary cardholder of an appropriate Chase MP credit card, are not eligible for CPU on award flights.
Correct, although I remember one post from someone who was able to get It done anyway, as an off-PNR companion at the gate. If there were a rule, I suspect it would be against it, but there's not actually anything that prohibits this (because off-PNR upgrades are an unpublished benefit).