I am flying UA853 SFO BKK, which stops in NRT. I have put in for an upgrade, and it is currently waitlisted. In looking at myItineraries this flight shows up as one entry. What if one of the two segments becomes available, I am assuming that I will be upgraded on that segment and then still waitlisted on the other. How will I know that this has happened, as it looks like one flight in myItineraries?

Thanks.