This innovative session used two "key moments" to interpret an action research case study of the ongoing reorganization of the Belgian Tax Ministry. Both the research and the session used a social constructivist framework. The reorganization consisted of these phases: contracting, exploratory, in-depth, advisory, implementation of the restructuring, and organizational change. The first key moment, the contracting phase, illustrated efforts to develop collaboration between the researchers and the Ministry civil servants. The second key moment, the design and execution of the training process to support the organizational change phase, illustrated efforts to change behavior at every level of the organization. (Contains 17 references.) (YLB)