We are flying out on an AMEX 241 in J in September, but it's open jaw - out to Tokyo, back from Bangkok.

On the outbound leg I have noticed space has opened up in F on the other Tokyo flight of that day (005).

I am trying to work out if there will be any fees to pay via the call centre if I want to swap the outbound to this flight? I have already paid an offline fee for the original booking. Does this count as an amendment or is it cancelling the booking and starting again?

All advice appreciated as always

dp