Script doctor
A script doctor is a writer or playwright hired by a film, television, or theatre production company to rewrite an existing script or improve specific aspects of it, including structure, characterization, dialogue, pacing, themes, and other elements. They are usually brought in for scripts that have been almost "green-lit" during the development and pre-production phases of a film to address specific issues with the script, as identified by the financiers, production team, and cast.