I think JimandBeth are right re calling AA with a TICKET number to apply credit...at least for a CANCELLED flight/refund credit. My notes re MY CHANGED destination (same record locator as for SXM) flight fare difference credit definitely said I would get a VOUCHER for 114.28 fare difference good for one full year. In their FAQs etc AA says vouchers sent by email, and you have to enter the voucher number and the piin number, provided in the email, to check a blance etc,
Would really like to know if anyone else expected a Voucher....and how quickly that was sent out (via email?) thank you