The role played by Faye Dunaway was first offered to Diane Ladd: Dunaway and Ladd had both appeared in the film Chinatown (1974) in which Ladd's character impersonates Dunaway's. Dunaway was given the role as she was agreeable to a lesser fee than that asked by Ladd and also did not wish the star billing which Ladd did.
Reshuffles at the studio resulted in director Tom Holland having a different ending imposed on him, largely at the behest (it was rumored at the time) of Faye Dunaway who didn't want to be seen in a bad light.