In Agile methodologies, it's important to remember that while each team member may work on specific tasks or "stories," the team as a whole is responsible for the completion of the sprint. This means that if one story is not completed, it's a reflection on the team, not just the individual who was working on that story. The Agile leader should emphasize this collective responsibility and encourage team members to help each other in order to ensure the completion of all stories in future sprints. References: PMBOK Guide, 6th Edition, Section
9.3.3.3: Team Performance Assessments. Agile Practice Guide, Section 2.3: Team Roles.