Harvard Business Review:

If you haven’t been getting along with someone at work, there are ways you can repair the relationship. First, ask yourself what’s happening so you know what needs work. Are you having trouble communicating? Are you failing to see eye-to-eye on things?

Give up being right, and resist your tendency to analyze every detail of what’s happened in your relationship. That’s not productive.

Instead, look forward and reflect on what you want from the relationship. Try to see the other person’s perspective. When you’re ready to approach him, make it on neutral ground. Go out for lunch or coffee, rather than asking to meet at one of your desks. Don’t debate what went wrong or who is at fault. Focus on the bigger picture or a common goal you share. But don’t expect the relationship to change overnight; it takes time to reestablish trust and reciprocity.

Adapted from “Fixing a Work Relationship Gone Sour” by Amy Gallo.