Originally Posted by
MarcusBWI
... Am I able to contact either United or Air Canada to get bumped up to business, since that's the class I paid for initially?
....
While UA has a process for this if UA operated flights,
Consolidated "Waitlist for Award Seats Questions/Issues", partner flights are considered an award change regardless of what you paid in mileage. In this case, while there may be no new mileage need, a new ticket needs to be issued if I space has opened for the economy segment and it most likely will be required the other confirmed segments need to be re-booked requiring new I space availability. This like a paid ticket, you will pay today's price for everything. While you might think you can just change one segment but that's not how it generally works.
In the past, UA allowed single segment changes and in most cases, it worked but a number of times it did not,
as the partner did not honor the other segments and the entire ticket was lost. There are agents that may be able to manipulate the system to make this work but the general answer is no. For short a short segment, I would not bother.
BTW, only UA can make the change as UA purchased the economy segment and the partner will want a higher payment.