Position and interestA position is what a person demands: “move me to another team,” “give me a raise,” “take him off the project.”
An interest is why they want it: recognition, fairness, predictability, growth, peace of mind.
Positions collide head-on: you can't give the same project to two people at once. Interests are compatible far more often: recognition for one person and predictability for another don't get in each other's way.
A classic: an employee demands a raise right after an interesting project went to someone else. The position is money. The interest is “show me that I'm valued.” Give them money, and the conflict stays and comes back.
The manager's key is the question “Why does this matter to you?” or “What will change if you get it?” The answer almost always opens up solutions you can't see at the level of demands.