One of the most common and least discussed causes of failed transformation is that nobody is clear on who does what. HR assumes the change manager is handling resistance. The change manager assumes line managers are reinforcing new behaviours. Line managers assume someone in the program team is managing stakeholders. The project manager assumes HR is leading the people side. Everyone assumes someone else is doing the critical work, and the gaps only become visible when adoption stalls. This article provides practical clarity on three connected questions: what is HR's actual role in transformation, when should you bring in external change management support, and how do you define new roles without creating the confusion and resistance that undermines everything else.