What happens when you disagree with what a director does with your script?
 Has that ever happened to you? Is there anything you can do about it?
–Jane
Disagreements can and do occur between writers and directors, and at least
 in terms of feature films, the director almost always wins. After all, it’s
 the director who is responsible for getting the film up on the screen, and
every department needs to support this effort. 
However, it’s important to distinguish between bad disagreements and good
 disagreements. Bad disagreements are easy to spot, because they often involve
 shouting and name-calling and vows never to work together again. While there
 may be genuine issues at hand, more often the battle is over ego, turf, money
 and fear. These kinds of situations are movie poison, and usually hurt the
 film.
Fortunately, most disagreements between writers and directors are good disagreements,
 where they may have different opinions on characters, scenes or plotlines,
 but argue only with the intention of making the best film possible. Remembering
 the first rule of disagreements (the director almost always wins), a smart
 writer will try to figure out not only what the director wants, but why he
 wants it, and how to best achieve the outcome without hurting the script as
 a whole.
In my experience, many directors use their writer conversations during development
 and pre-production to answer their own questions about the project: What will
 the movie feel like? Why is this moment important? How will I direct that actor?
 The more confident and secure a director feels about the material going in,
 the better the movie will hopefully turn out. So it’s generally worth it to
 set aside your defensive tendencies and let the director explore the material.
 Hopefully, you’ll find yourselves trying to make the same movie.
Disagreements during production are more treacherous, because exhaustion breeds
 paranoia, and every hour of filming is literally costing thousands of dollars.
 Often writers aren’t very involved during production, but if they are, the
 most important thing they can do is make sure the story is still being told,
 despite the obstacles and changes that arise.
In post-production, the director’s primary collaborator is the editor, and
 the two of them will have the same kinds of disagreements as the writer and
 director had during pre-production. The writer’s involvement during editing
 is unfortunately rare, but can be extremely helpful. The writer generally has
 the best sense of how the story was originally constructed, and can help nudge
 it back into shape.