Here's what to do if you find that you can no longer make your flight. If you want to cancel your flight, you have two choices1:

From the US and Canada, dial 1-800-998-6716 to reach the reservations department. All the time, this queue is open. Here you may also find customer service phone numbers for various languages.

Visit AA.com to cancel your reservation there. To find your reservation, you will need your 6-character flight confirmation code. Then, you can cancel it by following the on-screen instructions.