Waitlisted Upgrade on 3-Class Question
 

I'm waitlisted for a miles-purchased upgrade on a 3-class aircraft.

Business (my next class of service) is full - First is not.

Does that mean I'm SOL, or will United upgrade me to First if there's an empty seat?

Sorry to say, you're pretty much SOL. Outside chances that someone currently in C will cancel or will get upgraded to F, opening a possible C upgrade. But whether you'll get that upgrade is by no means guaranteed.

As a rule, UA will not grant double-upgrades.

Your hope is that someone in C is trying to upgrade to F (or gets op-upped to F), which would open a seat in C into which, depending on your position on the waitlist, you may clear.

Bummer, thanks for the reply.

It's likely that there's a waitlist for C pax to upgrade into F (assuming O=0). Once those clear, probably at the gate if the flight is coming up soon, then those open C seats will be made available to those on the waitlist. However, since you are using miles for the upgrade, you may be dropped off the waitlist at T-24 h based on some reports.