Los Alamos National Laboratory is a large science- and technology-based organization that has recently undertaken a major reengineering effort in an attempt to maintain its competitiveness in a rapidly changing world. Although the initial thrust was toward altering processes, management systems, and culture, it was decided that a major reorganization was needed as well. Along with the reorganization came a flattening of the management hierarchy and an almost complete change in the composition of the senior management group. This restructuring has had profound effects on the organization, requiring a new approach to management by the senior executives, and, at least initially, has swamped process and systems changes that will ultimately determine the success or failure of the effort. This paper documents the journey – how the structure and behaviors of the senior management group had to change to work in the new environment, trickle-down effects of reorganization, levels of decision-making, integrating processes and systems, and communicating with employees – and identifies some lessons learned that might be useful to other large technical organizations contemplating such changes.