Originally Posted by
ACR2013
Does that mean that once an original ticket is canceled and a flight credit issued, then you rebook using that flight credit (partially or in full/with extra payment) and cannot make further reservations (3rd, 4th), and funds from the original ticket will be lost? Or, is it only relates to OP`s situation when trying to use both Flight Credit and the leftover from the original flight credit i.e. voucher?
The latter.
Take a simple example:
1. Purchase a ticket for $500.
2. Change the date and the flight now costs $400. AA issues a credit for $100 which can be used for a new ticket,
3. Change the date again and the flight now costs $500 again. You will need to pony up $100 in new funds for the fare difference.
In OP's case, the credit for the fare difference for the first change can't be used to pay the fare difference for the second change.