Use the Pin tool to lock a modeling element in place. When you pin a modeling element, it cannot be moved. If you try to delete a pinned element, Revit warns you that the element is pinned. A pushpin control displays near the element to indicate that it is locked.
If you pin a component, it can still move if it is set to move with nearby elements or if the level where it is placed moves up or down. See Moving Lines and Components with Walls.