Oneworld awards cannot change routing under any circumstances -- this is one of the costs of using this type of award. AA did you a tremendous favour and broke many rules for you, hope you were suitably thankful. It won't happen again (in alll probability). Unlike most other awards, you cannot even change the airline between city pairs, the no-rerouting rule is that strict. Oneworld awards on AA do allow free change of dates, though (some other OW airlines allow no date changes on these awards, either!).