I called united to get put on a upgrade waitlist for the domestic segments for my business class award to Amsterdam. One segment (AMS->FRA) is on Lufthansa. Agent said if I was put on upgrade list for my SAN->EWR or ORD->SAN and the upgrade cleared, there system would send a message to Lufthansa which could cause them to cancel my AMS->FRA segment. This didn't sound right to me. Agent said to keep on checkng back to see if 1st class space opens on the domestic segments. That seems like a pain. Any advice?