In the summer of 2000 I flew to London after I was just divorced. My passport and ticket had to be in my new name (I went back to my maiden name) but my DL Skymiles account still had my married name. I wasn't even able to put my DL number on the ticket, when I got back I had to write a letter to DL and send in all my flight info to get credit for the flights.

On domestic flights I was able to use my Skymiles # with my old name, but not the international ones and this was way back in 2000.