If you think that one through it seems like doing this for a movie would be a logistical nightmare. Most actors are pretty good about learning their lines, which means you’d couldn’t just put random changes in because otherwise their time would be wasted. I’m guessing that it’s only used for pivotal plot changes like the Roddenberry incident describe on Wikipedia. Seems like the path used these days is extreme lawsuit threats built into their contract, something you’ll see just about every Marvel star joke about during interviews.