While you can copy almost everything and move the copy nowhere but keep it in place, doing so is tedious. You can never be sure that there is not a little fraction of a unit showing up when eventually clicking. The idea is to provide the context menu with a duplicate entry. The duplicate would then end up being the active object, that is the one with the new Revit-Id. Ready to be altered concerning its sketch, type or anything really. Please do not bother about a warning showing up that two identical pieces are in one place, because that is the desired outcome. I will now finish off the other half of the ceiling I was just editing.