Well... I just joined Raketherake after browsing through the forums, and they'll actually send emails out to get the "affiliate" changed. I was on Absolute Poker w/o rakeback and they added it for me. Only major condition was that I had to make another deposit and play a single hand. Not a problem as I can withdraw some, then redeposit it in a week to get credit for it
But, that was with Absolute Poker. Is your "affiliate" saying that FTP won't allow it? Did you sign up with some sort of deal? For example, though this involves 2+2... you sign up through them and they give you free books. They're now you're "affiliate" and you can't change it to someone who will give you rakeback. It's a GREAT deal if you're someone who plays in micro limits and dont' generate a lot of rake, but if you do and the "rake back" is worth more than the goods you received (like a set of poker chips on some sites) than you loose.