Realize that the person in question is the company's employee, not the manager's employee. Far too many managers see their position as some kind of feudal lord

Realize that the person in question is the company's employee, not the manager's employee. Far too many managers see their position as some kind of feudal lord where those beneath them on the hierarchy owe personal allegiance to them. If the manager doesn't like the person, that's quite possibly the fault of the manager, not the person. The manager shouldn't automatically be the one who stays if no working relationship with the person in question is possible.