NASA has three more operational Starliner missions on the books. It hasn't decided whether it will commit to any more than that.
https://www.wired.com/story/boeing-starliner-return-nasa-contract/?utm_source=dlvr.it&utm_medium=blogger
https://www.wired.com/story/boeing-starliner-return-nasa-contract/?utm_source=dlvr.it&utm_medium=blogger