This study of business process reengineering within a UK hospital engages with the following phenomena of interest to organizational scholars anmd practitioners: corporate change programmes; new forms of organizing; and knowledge processes in and around organizations. A hospital change programme is conceptualized here as a form of knowledge management whereby organizational leaders used business process reengineering in an management whereby organizational leaders used business process reengineering in an attempt to effect change organizational arrangements and performance. Utilizing Cook and Brown's distinction between knowledge and knowing, the article observes shifts in the ambition, organization and practice of the reengineering programme over time. Data linking the process and performance of the reengineering programme suggest that viewing reengineering, and other best practice concepts, as objective transferable knowledge resources is of limited theoretical and practical utility. Rather, the encounter between reengineering as `off-the self' prescription and the hospital setting reveals the interaction between `knowledge' and `knowing' to be a social process more subject to politicized relations and arrangements than presently theorized about organizational change, learning and knowledge processes. Other observations emanating from the study are that greater attention needs to be given to assumptions of knowledge transfer and use within debate about best-practice concepts and corporate change programmes. Possiblities for transforming organizations to effect new organizational form and process are also theorized as more complex than some contemporary writing suggests