Hi all, I am pretty new to using GPU so could use some advice.

I would like to book a ticket from PHL to LHR on 14th Aug RT 19th Aug, and use a GPU to upgrade from the US to LHR (there is 1 stop off either in IAH or IAD from PHL).

On checking the website, i clicked "MILEAGEPLUS UPGRADE AWARD" on advanced search. All the flights came up but each one said upgrade not available.

Am I doing something wrong or is that confirmation that I cannot use a GPU for those flights?

I know folks here talk about checking R availability. Can someone quickly explain how best to do that?


I appreciate the assistance