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.
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 Move Lines and Components with Walls.
To pin and element, do one of the following:
 Modify panel
Modify panel
 (Pin).
 (Pin). 
   Modify panel
Modify panel
 (Pin), select the elements to be pinned, and then press 
	 Enter.
 (Pin), select the elements to be pinned, and then press 
	 Enter. 
   Selection panel
Selection panel
 (Activate Controls). Click again to hide the pushpins in the model.
 (Activate Controls). Click again to hide the pushpins in the model.