How do you reconcile with people whom you burnt your bridges with?

Suppose you stopped talking to some people (e.g. a clique at your high school) because you found them irritating and didn't think you'd need them again. If you now, you end up working with the same people and you find that you need them, but they still hold a grudge against you, how will you build your bridge again? ..i.e. develop a professional rapport with them.