Originally Posted by
guv1976
If you have sufficient miles in your account currently, book the lower-priced option now, and immediately cancel the original booking. Your miles and cash paid on the original booking will be refunded.
If you do not currently have sufficient miles to purchase the cheaper award, put that award on a complimentary hold, and then immediately cancel the first booking. Once your miles are refunded, you can then complete the purchase of the held award.
Act quickly, while the cheaper award is still available.
AA's system may not let you book the new one (it wouldn't let me do it for the same itinerary at lower prices). I had no choice but to cancel the current one and cross my fingers/hope that I could still book at the lower price. You can open two browser windows (different browsers) to try to make things as quick as possible.
Supposedly the other option is to hold the new itinerary (again, AA's site won't let you do this) without somehow attaching your AA account # to it. Not sure how one puts an itinerary on hold with miles without their AAdvantage #, but apparently it's possible.