Meet with each manager to understand what their issues are and listen to their story. Ask them to start at the beginning and to pinpoint when and how the disagreement escalated. Ask them what they have done to manage and resolve the conflict.

Keep asking questions and listening attentively to the response. Listen to what they are saying, but also try to pick up what they aren’t saying. Ask more questions and pay attention to tone and body language, as well as their response.

You need to get to the heart of the issues. Be aware that the trigger of the conflict is more likely to be emotional than factual. So, ask them how specific actions made them feel or why they felt so offended.

Organize a meeting for you and the two managers in a neutral and confidential environment. First, agree on the critical problems to address using the information you gathered from the individual meetings. Aim for no more than three key issues and confirm these with both parties. Then, ask each manager how they see each problem, allocating enough time for each person to speak without interruption.

Give them the chance to question one another respectfully. As much as possible, seek common ground. Based on what you’ve heard, identify and propose solutions to each of the problems. You don’t need to offer solutions with win-win outcomes, but they need to be something that both managers can live with. Reiterate the negotiated solutions in plain language, document and get each party to sign. Finally, agree on a review period.

After each manager has had time to digest what happened, meet with each person alone again. Check on how they’re feeling and ask them to talk about how satisfied (or otherwise) they are with the meeting outcomes.

Make sure that both parties are accountable. Without follow-through, there’s a good chance that all the time and effort resolving the issue will be for nothing. The solution needs to be followed to the letter, and you need to check in regularly.