We have become the custodians of one of our larger client's drawings. We must check them in and out as they are required and sometimes the drawing is needed by more than one company at the same time. Company A is first so they are working on rev.2. Company B needs to start work right away, can't wait for rev 2 work to be done. How do we write a procedure telling company B what they must do? Should they xref a read-only version and work in a temporary drawing, then once the rev 2 drawing has been released to them combine it with their rev 3 changes? Can they turn demolished geometry to a non plot layer to show the new geometry in its place? Does anyone know where I can find a written procedure for best practices on this?