Possibly, but you likely won't get anything anyway. What they would do is reprice the one-way, and offer any remainder, if they agree to refund the return. Problem is that one-ay trips are often more than round-trip, so the net may be negative.
I would call AA to ask because they can look at the specific situation. But I wouldn't count on muhc.
Cheers.
Not so. yes, if it was a voluntary change. But the OP should ask for an involuntary refund. I have had them processed several times by AA and other carriers. DL even refunded half the miles on a Skymiles roundtrip redemption.