option for redirect or not when terms are changed

I would want a option for my terms where i can say if users need to re-accept the terms or not when i make a change. Because i use rules to send the user back from where he logedin they get send back to the accept page.

User logsin -> legal makes a redirect to the new terms, user accepts presses button -> rules make redirect to last page, that is terms -> user again accepts -> gets send back to frontpage with a error because they have accepted the terms twice.

So basicaly i would like to turn off the option to make users re-accept the new terms.