The AAdvantage rules for OW awards are no routing changes, at any price, and date changes are free. They did you a major favour (technically the only way to do a routing change is to redeposit the award and issue it from scratch, which includes losing any reserved space you already have!). Be sure to say good things about how wonderful AA is, wish they would do such favours for me. The other OW airlines have far more restrictive rules for awards (BA would not allow a date change, much less a routing change, for this same award, as well as charging roughly triple the miles). Note that the OW award rules are completely different from the other AA award rules!