I would like to book an aeroplan ticket, but the return DCA-YUL only has availability via YYZ. Question is, can I get to the airport early and standby for a direct flight for $50? Or is this considered an itinerary change and hence illegal.

I called AP about this and the agent put me on hold while she went to investigate. Her answer: there is no rule about this so I can't say yes or no. It will depend on the agent at the airport.

Can anyone give me a sense about this? Thanks!