I track them down and make them regret their betrayal by forcing them to eat an entire jar of Mayonaise and not the good kind either.
Kidding aside, Satan is pretty understanding from what I've heard. I'd not break my vow, but if you are concerned that things may change in the future do your meditations, work toward the magnum opis and your desires, help Satan and then when it feels right then dedicate. I didn't dedicate until about a year after I started meditations.