This is my first time attempting this so I am sure I'm missing something basic.
United 1K, ticketed on UA stock. I'm booked in premium economy on the 2nd and 3rd legs.
HSV-IAH on UA, IAH-YUL on AC with an AC flight number, YUL-CPH on AC with a UA flight number.
The PNR viewer shows that I'm in "R (A)". That's not one of the fare classes supported for UA PlusPoints upgrades. AC bid upgrade doesn't work-- I suspect because I'm on a UA ticket.
My current plan is to see if I can buy an LMU gateside when I get to IAH. I don't really care about IAH-YUL but would like it for the longer flight. Is there any other way to buy an upgrade (besides just buying up to J, which would send my travel department into a fit of poop-flinging)?