I'm flying SFO-YYZ on Thu night, ticketed as UA 3218, but the flight is actually AC 754.

I called UA this morning on another matter and before hanging up asked for an upgrade based on my newly-acquired PE status and, as I expected to happen, was declined on the obvious grounds that the flight is an AC one and it was suggested that I contact AC directly.

I then telephoned AC, and they noted that I was ticketed as UA, and then asked whether I had UA upgrade certificates - I replied that I had both UA and AC certificates. The agent was confused on how to go about upgrading me and sought out her supervisor to clarify matters. The supervisor stated that I can't waitlist for an upgrade under the codeshare circumstances using either set of coupons and I would only be able to upgrade at check-in/gate.

So, it seems that I should have not chosen a different ticketing carrier than flying carrier as despite having status on BOTH AC and UA - I'm still being sooooo discriminated against