Does AA charge for making flight changes?

I saw this on their website:

Flight Change: Once a booking number has been issued, flight changes are subject to the following terms:

Inside of forty-eight (48) hours prior to the scheduled flight departure time, no changes are allowed. The charges for flight change outside of forty-eight (48) hours prior to the scheduled flight departure time are provided for in the fee schedule, subject to the following conditions:

if a lower fare is available, the difference in fares will not be refunded to the passenger;
if the new flight booked is in a higher fare class than that of the cancelled booked flight, the difference in fares shall be paid by the passenger before the cancellation or change can be made;
the change is not confirmed until we issue you a new Itinerary and/or booking number.
changes on route(s) are not allowed.


If I am not wrong, there is no additional chagres (service charge), but ofcox if the ticket is higher, you have to make up the difference.

but i also heard that they charge.

can anyone advise?

thanks