I just had points transferred into my account from another owner. She set up the 3 way call with me being on hold while she told MS all of her personal information, and advised that she would like to transfer her points to me. I was then patched into the call for MS to review the "legalities" of the transfer (i.e. points maintaining home resort priority, no more transfers this year etc.). As the person receiving the points, it was painless. I called MS approximately 15 minutes later to confirm that the points were in my account, and book my vacation!
According to the person who transferred the points to me - MS insists on a 3 way call now, and they won't arrange it for you.
Hope this helps