Circles aren't always the best way to address an interpersonal conflict unless it escalates so much, the two sides don't want to talk to each other. It's generally effective to resolve a conflict between two people face-to-face, unless one of them feels vulnerable in the presence of the other, then a third person should be present to support them.
Before you approach the person to resolve the conflict through conversation, try to cool off and ask yourself:
What might have been the reasons for this person's behaviour? What is it like to be in the other person's shoes? Am I ready to listen to their point of view? What are the possibilities to resolve this situation? What do I expect from this conversation? Eg. simply an apology or some form of atonement? Will this solution satisfy me? Will the other person agree with this solution? What if not? Do we need a neutral third person to facilitate our conversation?
Sit together in a place where you won't be disturbed and can talk openly. First, each person needs some time to state their position - when one person talks, the other should not interrupt at all under any circumstances. They too will have a chance to speak uninterrupted. (This is where a third neutral person is useful - they can ensure both are treated fairly). Then you start a conversation in which you can refer to what you have heard from each other. This might turn into a heated discussion for a while, however bare in mind that you don't want it to go on forever. Once you hear arguments are being repeated, you can assume the discussion won't move much forward and it's time to focus on expectations and solutions.
The goal is not to win over somebody, but make the relationship with the person and relations within the group a priority and ensure you remember about the great value of learning something new about yourself and others that this situation brings.
Be open and willing to forgive - otherwise resolving a dispute isn't possible. Know when to stop and agree to disagree. Be specific about what's bothering you and why. It's easier to work on concrete things. It's easier to understand a different point of view when you know what the person's reasons to think as they do are. Avoid attacking and accusations, instead talk about how the other person's actions made you feel. Don't let grievances accumulate, attack the problem, not the person.