To produce business results, the globally integrated enterprise relies on people to collaborate, make choices, and take action. Though guided by process and enabled by technology, people's behavior is powerfully influenced by leadership and capacity for change. Facing continuing and sometimes large-scale transformation, IBM chose to add organizational change management to its core capabilities. This capability, coupled with a newly centralized worldwide IT (information technology) organization, enables a systemic approach to the adoption of global internal transformations by IBM employees. The Blue Harmony transformation program is the premier example of the IBM focus on organizational change management. It is considered by many to be the most significant operational transformation of IBM in decades and sets the operational foundation for the next 25 years. As part of the longer-term strategy of IBM to integrate the enterprise, it simplifies, integrates, and standardizes operations globally and across business units. When fully implemented, Blue Harmony will change the daily work of nearly 200,000 employees as well as clients, business partners, and suppliers. In such a massive transformation, the challenges of managing change become massive as well. Lessons learned reveal the effort needed to manage stakeholder expectations and engage executives across the enterprise in leading major change.