I have an international ticket issued on a *A partner. The way I read this thread, I cannot use my Regional Upgrade to upgrade the UA operated domestic flight. However, I might be able to get an upgrade on the day of departure at the United check-in or gate. Is that right?

Once I called UA to put my MP# into the United record I was able to see my reservation in "my itineraries". However, it would not let me upgrade online. So, I assume I can try when I get to the airport.

In all honesty, I'm not sure that it is worth upgrading since I'll have access to all the lounges before and after the flight, so I'll get food there. Since I
do have economy plus seating, maybe I should just use the upgrades when I'm on a domestic itinerary sometime and don't have lounge access.