American Airlines change Policy
American Airlines' flight change policy for award tickets states that miles will be credited to the AAdvantage member's account. The process happens automatically after change, unless it's an AA basic economy ticket or a non-refundable ticket.

Refunds for American Airlines tickets in the form of credits/vouchers/miles may take up to 7-10 business days. Mileage reimbursement is usually refunded to your account when the reservation is changed.

How to change an American Airlines flight?
If you're wondering how to change American Airlines flights, you'll be glad to know that the process is very simple. Passengers can change their tickets through online and offline methods.