I just wanted to check what the policy regarding an unused ticket. A friend of mine had a non-refundable ticket YUL-YVR for reading week but due to some problems with exams and traffic, and the fact she left it to close to get out to the airport she ended up missing the flight, and all the flights were overbooked for the next three days so she couldn't get on standby. Now she wants to go to IAH and the fare is a bit less than the value of the original ticket. We were told at YUL once she had missed her flight that her credit was the value of the ticket less the $145 change fee, which would be perfect, however when she called AC they wanted her to pay the change fee up front, rather than deducting the value from the credit. I was wondering if you guys had any idea as to what the official policy is, and whether I just got a bad agent and should try calling again.

Thanks