Here is a 10 step process of interpersonal negotiation that might be helpful.
1) The parties involved in the conflict should come together
2) Each party should take a turn describing his/her perception of the situation, how he or she feels about it, and what he/she wants. The other party should listen and then reflect the other's perspective.
*By reflect I mean restate what they heard the other say
3) Together, parties should come to an agreement on what the conflict is really about. (This may take several iterations of step 2)
4) Each person should agree to be willing to come up with a solution that encompasses both parties' interests.
5) Together, parties should describe their ideal situation.
6) Parties should come to an agreement on a new ideal and realistic situation
7) Talk about what changes will be needed to bring about a new situation
8) Together, make a plan of action which will help achieve the desired new situation and set a time frame for these changes.
9) Make a commitment to make the necessary changes.
10) Set a future date to evaluate the situation and to re-negotiate any differences if necessary.
*Obviously this process is not going to happen with bells and music playing the background like a dream, it takes hard work, and often requires humility and trust to be established and given. Sometimes it even requires a 3rd party to help us walk through these steps.