Originally Posted by JDiver

There’s no such thing as an AAdvantage miles round trip award ticket; all miles awards are one way. You probably have two 12,500 mile awards on the same PNR.

You can cancel without a problem. If you cancel the second hal before you’re due to fly it, you can get the 12,500 miles reinstated - at a cost of $150 unless you’re Concierge Key or Executive Platinum, as you are, or AA cancels your flight(s) or substantively changes your schedule.