Hi, I am going on my first trip to Africa in a few weeks. I purchased a ticket on United without realizing that it was a "non-upgradeable" class of ticket, and got a Mileage Plus VISA so that I could accumulate lots of miles before the trip. I have enough mileage to purchase the upgrade for the trip, but can't do it in advance because of the class of the ticket. However, mileage plus phone staff told me that sometimes it might be possible at the last minute on the date of the actual flight. Does this mean I shouldn't do in advance check-in on the computer the day before and would be better off to actually check in for the flight at the airport? I realize my chances of getting an upgrade are probably slim with this ticket, since others will have priority, but wanted to see if anyone had any hints on strategies! Thanks in advance for any ideas. I am flying LA-Dulles, Dulles-Johannesberg (the last half on South African Airlines). Can you sometimes get an upgrade for just the second leg? I don't really care about the LA-Dulles part.