Originally Posted by
CIT85
I am not aware that it is even possible to upgrade a companion who is not on the same PNR. I have always applied my RPU when my family travels with me and we're on different PNR.
its possible to have a companion from a separate reservation added to the waitlist. However, it can only be done at the airport, as far as I know. And haven't tried in a while, but IME, and I mostly tried to do this within the first year or two after the merger, only some agents know how to properly do it.