I just flew US Airways and had the miles going to United. After the flight, I decided I wanted it to go to A3.
I called US who said that for the return trip that didn't post yet they could switch but for the outgoing flight that already posted to UA - I need to call UA, have them release the miles and then call US back to send to A3.
I called UA who warned me that once they release them, I can't change my mind and send them back to UA and the system won't accept miles from that same flight again. They said it takes 48 hours.
Once the miles left my UA acct I called US and they now insist that there's no such thing as getting the miles released back to them and that my miles are in no mans land and can't be retrieved. I spoke to supervisors etc who all insisted that I was misinformed by the original rep and there's no such thing as UA releasing them back to US to then be transferred elsewhere.