Here is my 10-Step plan.
1. Prepare. Make some notes about the situation and your feelings. Write about where you are, where you want to be, and how you might get there.
2. Be willing to come to the table and stay there. The others will come if your message is, "I truly want to find solutions that works for all of us. We are in this together.”
3. Set the stage. Sit down at a time when you are all clear-headed and able to give this important conversation the time and energy it deserves.
4. Speak from the heart. Do not point fingers of blame. Instead focus on finding a solution that works for both of you. This is collaboration.
5. Listen, listen, listen. Listen as if you are an outside observer with no prior knowledge of the situation. Twenty years in the mediation business has taught me that there are at least two sides to every story. You may be very surprised when you hear the rest of the story.
6. Give yourselves time to think, process the information, and cool down.
7. Define the emotions. Under almost every human conflict -- be it two kids in the schoolyard or two nations at war -- someone feels dismissed, discounted, disenfranchised, or disrespected. These are the emotions that fuel the feud. Sometimes, just defining that emotion and realizing that both of us feel the same way is enough to resolve our dispute.
8. Be willing to apologize. The closer the relationship, the more likely you are to have stepped on each other's toes. If you cannot bring yourself to apologize for anything specific, at least apologize for the distress that the other side has been living with and anything s/he believes you did to contribute to it.
9. Don't leave conflicts unresolved. An agreement to disagree is resolution. Leaving the conflict open sets you up for future fights.
10. If all else fails, hire a professional to help you. Often an outside opinion sheds light on your blind spots and helps to reach agreement. Consider bringing in a mediator. Your situation affects you personally and professionally -- now may not be the time to be a do-it-your-selfer.