Finding two incredibly hard-to-find NZ C award seats from AKL to SFO on the same flight, I booked both, failing to request 2 PNRs. My wife and mother will be traveling. But my mom may need to return later. UA says they can't split the PNR without releasing the award seats, risking the possibility they won't go back into inventory or that they may be snapped up by someone else within minutes. UA says the only thing to do is for one passenger to simply not show up, in which case I can get the miles back for that traveler. But since you're supposed to cancel Star Alliance awards 24 hours in advance, I question whether the miles really would be returned. Any thoughts?