It is very strange. I chose full fare on AA.com and booked the tickets from NYC to PEK. I called to upgrade and was put onto the waiting list. One CSR said I need to pay co-pay to get upgraded because it is a W class. The other CSR said that I only need to pay 15000 miles with no co-pay.

Which one is correct? If I need to pay co-pay, I prefer to cancel the tickets within 24 hours. Thanks all!