American does not charge a penalty if you change your flight within 24-hours of booking, if you need to make a change to your trip. For any query, call. The same-day flight change option will be available within 24 hours before your original scheduled flight. The flight you request must be leaving within 24 hours from the time your request is made and can include any fare class, though you may have to pay the difference in fare. The cost to change a American flight can vary depending on several