You just tell Satan that you don't want to be dedicated to him anymore and that's that ritual. In fact there is nothing mystical in dedication or the reverse of that, you just say you want to be his discipline or not, and that's it.
Again, dedication is not just mere words, but acts. One was never dedicated, if they did not really want to be dedicated and never did anything for this matter. And one can become un-dedicated if they want to be, and stops doing anything for that matter.
If dedication would be what a newbie thinks it is, than every human would be dedicated. Every human is the children of the Gods, their descendant. We are their creations, so than every Human has a strong connection to the Gods. But what we mean under it is the amount of effort one gives for advancing both themselves and their environment trough various means. This is the commandment and the will of the Gods, that's what they want us to do. The dedicated do as the Gods says.