The usual thing is an actor gets offered a role, and signs on. The contract can often leave him at the mercy of the production company - there are plenty of stories of actors having scripts changed on them, or films edited into something completely different, without their ability to have any input. Usually, unless they have lots of clout, they can't have any influence on the disposition of the final product - to prevent release of something is pretty much impossible. They try to select a good project based on a good script, and a good group of people doing the production. Then they do their job, go home, and hope for the best.
Then the production studio makes decisions about how to distribute the result. They may decide the film is unmarketable, and write it off - there are stories of multimillion dollar embarrassments languishing in film vaults - or they release with anything from no promotion, direct to DVD, to major theatre placement.
The actor can only choose what to do based on paycheque, or artistic interest, but preferably with an eye to what it can do for their professional stature. Sometimes signing on to a riskier production can result in a great performance, and things work out great; and sometimes what looks like a good idea crashes and burns.