Originally Posted by
EnvoyBoy
I'd be curious if anyone knows the answer to this.
I'm thinking it won't because the few times I've switched my FF numbers, I was asked if the flight in question was my outbound. It's led me to believe that once the trip has begun that such a change can no longer be made.
I was told by a gate agent in 2006 that once you can't change your ff number at your connection airport. But you can have one ff number outbound and another return.
As for first class travel with a UA number -- it IS possible. (Or was possible.) Thanks to my messy desk I have here in my hands a bp for travel CLT-SFO Sept 2006, seat 3F (First) and it has my UA number and reads "United Premier UA*S-Star Alliance Silver".
So, at the time at least, it could be done. If I remember how this happened I had called US the day before my flight because I wanted to check on my upgrade (I was a Silver at the time). For some reason my status wasn't in the system, he fixed it, the computer gave me a first seat and I said "What would happen if you put in my UA #?" He (and I) thought it would take my seat away, but he tried it and to our surprise I kept the seat.