Depends how it was booked. Tell them that agents in the past have said if you book on PTO or website, to just book and call the agent to get them to change the fare. (this is what PTO agent told me). Now if you have waited a long time, it might be difficult to do, but if you just booked it and then phoned them, they should agree. I would ask for a supervisor.


BlondeBomber's Pet Peeve (and Tuesday rant)!
This is a big problem with Air Canada's (and other airlines booking engines) site and PTO which I have written on numerous occasions to AC and been assured that it will be in the next revision (now almost 2 years ago I had that promise made). Their idea of booking by fare class seems to be allowing you to ONLY choose from discount econo, unrestricted econo, or business.

They were the ones who put the V class fare rules in place, they should at least allow you to check off "upgradeable" fare. Not rocket science for IT people but they seem incapable of implementing it despite many promises and assurance to me that it would be done (both by e-mail and by phone).