Another related question.

On one of the trips I have booked I have Business outbound and Economy inbound. Should more award inventory become available for the inbound, I would be able to call and rebook (has happened before and did so on a HND flight last year - but maybe based on the above it was a risky move?).

Also, calling in often takes a very long time (long wait, slow agents). Would I in stead be able to simply book a one-way Business ticket for the inbound trip, and then call in and cancel the inbound leg of the original booking but keep the outbound business flight? I would of course have to pay the cancellation fee but I am not sure whether it is possible to cancel an award ticket partly?

Would I even be able to also add a domestic flight (ie. add a CPH-AAL leg to a YYZ-CPH trip) to the new inbound Business ticket, in the event that there is no inventory for the inbound domestic flight?