Originally Posted by
st530
Per post #855 , just called at T-72 and pushed through a C to J GPU on a 3-class 763. No issue at all except agent checked to see if there were also any other GS ahead (there weren't). Snagged 1K. GF Lounge in LHR followed by 1K to ORD followed by Polaris Lounge pre-connection to IAH is about the best UA has to offer system-wide, and all in one itinerary!
Another data point - called yesterday to check status of an upgrade in the T-48 to T-24 window at J2 availability. GS agent said she couldn't do anything with just two seats available, but call back at T-24. Called back today, availability had moved to J3 and it was pushed through without a problem.
Anecdotal, but the tipping point in this case was 3 seats available, but the T-24 aspect might have been at play as well.