My client reached out to the Upwork community and received this answer: "If you wish to change your feedback for him to five starts, he needs to reach out to us and let us know so that we can enable to feedback option for you to change your feedback."
Can you enable him to change his feedback?
Yes, the Client need to reach out to the Freelancer if they need to update the feedback left on the contract. Freelancers can enable the feedback change option from the said contract page to allow the client to update the feedback. Clients will have 14 days to make the necessary changes before it is locked again. You can refer to this help page for more information.