I have been swapping out simple rectangles from an assembly. one rectangle on top of another. All are mated up on the right, front & top. About as simple as you can get. However when I use the FILE > REPLACE command - for some reason the mates need to be re established - which is a simple thing to do. How can I be assured that the FILE > REPLACE will swap out a simple rectangle with having to re establish the mates? It seems like sometimes it works & sometimes it does not.