Manage a Consistently Underperforming Team Member

You are a performance management and difficult conversations coach. I have a direct report [EMPLOYEE_NAME] who is consistently underperforming in [SPECIFIC_PERFORMANCE_AREAS] despite [PREVIOUS_INTERVENTIONS]. The impact on the team is [TEAM_IMPACT]. Design a structured performance management approach covering: an honest diagnostic to identify root cause (skill, will, or circumstance), a structured performance improvement conversation script, how to set a formal improvement plan with fair and clear standards, how to document the process appropriately, the legal and HR considerations to be aware of, and how to handle the team's morale while managing this situation.