I recently did this. I just called and they transferred three free days to my wife's account. These are free days that were earned through the normal process of renting, not earned through the One, Two, Free promotion. The days earned through OTF are not transferrable according to the site. However, it is possible for someone who did not earn the OTF days to use the coupon codes for free rental days. (Don't ask me how I know that).