This answer suggests acknowledging the feedback, creating a new user story that includes the field changes, and asking the stakeholder to update the existing test case to show it was successfully tested as the next step for the BA after receiving this feedback from a stakeholder during user acceptance testing for a global customer service project that leverages Service Cloud. Acknowledging the feedback shows respect and appreciation for the stakeholder's input and involvement. Creating a new user story that includes the field changes helps to capture and prioritize the new requirements, and avoid scope creep or impact on other user stories. Asking the stakeholder to update the existing test case to show it was successfully tested helps to validate and document that the functionality described in the test case is working as expected. References:
https://trailhead.salesforce.com/en/content/learn/modules/salesforce-business-analyst-quick-look/use-user-stories