Thank you for your reply!
In my project the designing draftsman and the designing engineer work on the same model.
The designing engineer wants to lock the analytical model so that he can see the changes the designing draftsman has incorporated. He does not want the analytical model to change automatically because some changes are insignificant and he does not want to adapt the analytical model whenever the geometry changes.
I don’t know how to do that in Revit and I did not find anything useful through the search tool and/ or Google…