Originally Posted by
satprof
You are looking at a routing change, which is 1(b), if done before departure from YYZ.
I would recommend going with MiamiPrep's suggestion, so that this re-routing becomes a change after departure, and hence subject to rule 16 2(b), so you should only need to pay the $125 fee (plus any service charge AA might find). If you have an e-ticket, you won't even need to get it rewritten.
There used to be a rule about international segments, but these don't seem to be in the current rules, and, for a different purpose, USA<>Canada was not deemed to be an international segment, so I wouldn't go there!
The rule is still there:
(f) Only one international departure and one international arrival from/to the country of origin permitted
EXCEPTION: Two permitted for origin USA when one arrival-departure is a transfer without stopover.
NOTE - travel between USA and Canada is not counted as international.
I'm not sure your plan will work as US-Can has always not been considered an international segment and TC1 has always had that limiting rule for changes(another reason not to start in TC1).
Tied in with the 7 day no changes rule is the 7 day reservations rule:
(a) Reservations and Ticketing
For travel originating in TC1
Reservations for the first international flight and all preceeding flights are required at least 7 days prior to departure of the first flight. Subsequent segments may be open-dated. Tickets must be issued at least 7days in advance of the first flight.
Exception:
For economy class reservations made 22 or more days before departure, tickets must be issued at
least 21 days before departure.
AA might stick to their guns and make the OP fly that MIA-GUA segment before allowing changes.