If both AE and AC were to spend some time making their online booking engines far more robust, I dare say they'd have far fewer calls.

Suggestions such as;
-Allowing changes to a flight that has been upgraded. If the new flight doesn't have the availability....then no upgrade. Simple as that.
-Allowing to use canceled tickets to book new tickets.
-Allowing to book multi city itineraries that include travel between 2 cities not flown by AC. (Canada-Europe on AC, Europe City-Europe City on Star Alliance, Europe City-Canada on AC)
-rebook/modify itineraries by canceling, crediting then using credits for new flights.