When a disagreement with a coworker spirals into the kind of fight where you regret your words and actions, you need to be proactive about mending the relationship. Set up a one-on-one meeting with the other person. Your initial goal is simply to apologize, so specifically acknowledge what you did wrong. Then say you’d like to discuss what happened and how to keep it from happening again. (If emotions are still running high, it may be better to pause the discussion here for a day or two.) Think through the incident together, identifying when the situation turned negative and why. For example, if you got upset because your colleague seemed to take credit for your idea in a big meeting, talk about how to make sure everyone’s contributions are publicly acknowledged. And be sure to express how much you care about having a collaborative relationship. Highlight what you value about the colleague’s work, and discuss how you two can rebuild trust.