I suspect their rebooking process is rather backed up right now with all the flights AC is cancelling, etc. Usual procedure is to advise passengers within a 2 to 3 week window, then work on those on flights further out who are left. However, if you made the res yourself, you can always call AC and let them rebook you while you wait. This way you can get the best connections [and you'll be earning an extra 1000 Aeroplan Q-miles for the BD sectors] and seats on what will surely be filled 747s and A330/A340s. Why wait? If you made the booking through a travel agent, call you agent and have him/her rebook you.