It's free to switch the flight of an american airlines change fee award flight, but you'll be required to pay for any additional miles for the new flight. If the new flight cost less American AAdvantage points, any difference will be transferred to your account. If you've utilized miles to upgrade a flight, you may modify the flight without charge by contacting reservations.

A key difference is the fact that American currently offers three types of award tickets anytime, MileSAAver and Web Special. AAnytime MileSAAver, AAnytime as well as Web Special. Web Special award flights are generally the cheapest however they are not able to be modified.

However, in reality this shouldn't be an issue as it is possible to cancel the award trip at no expense (including Web Special awards) Restore your miles, and then use those miles to book the flight you want.

More Info:- delta airlines reservations | united airlines reservations/