When I called I just said, "I was IMing a friend about the new NFL season and signing back up, when he mentioned that he got all this for being a long time subscriber. I was wondering is it possible for me to get in on this deal?"
That's what worked for me, but I also only called once. I was also polite, but I think some of it had to do with the luck of the draw on who I got in the retention department.