When a stakeholder's role within the company changes but they remain a stakeholder in a project, the project manager should ensure that the Communications Management Plan is updated (Option D). The Communications Management Plan is a part of the overall Project Management Plan that specifically outlines how, when, and by whom information will be administered and disseminated. This plan should be revised to reflect the new role of the stakeholder to ensure that communications are appropriate, effective, and directed to the right individual in their new capacity. Adjusting this plan helps in maintaining clear, accurate, and timely communication flows, which are crucial for project success, especially when stakeholders' organizational roles and responsibilities change.