You should call AA. Most/all? BE fares can’t be up fared. But this is international and that potentially brings in a whole new set of rules. Also for tickets purchased on/after 4/1 BE fares aren’t changeable/refundable, so a lot will depend on when u purchased ur tickets. Call AA.
I have a basic economy fare to Europe, and just realized that I would rather fly in business. What is AA's policy regarding paying to upgrade a basic economy fare to business? Also, if I were just to cancel, it looks like the actual fare is $1, and the taxes are $298. If I just cancelled and then rebooked later, would I get a refund of the taxes and fees, even though the fare itself is nonrefundable?