Collective reflection has been a long-term issue for scholars and practitioners. Yet, being conceptualized as a shared, discursive practice that is dynamic and supported by structures in organizing, existing studies fall short on explaining and illustrating empirically how collective reflection emerges as such a practice in organizations over time. We apply a Heideggerian-inspired practice perspective to address this gap. Drawing on a longitudinal study of a lean implementation in a Swiss regional hospital, we illustrate the development of various communicative platforms and coordinating mechanisms and explain how these together and over time result in an increase in organizational awareness. The research generates two core insights: First, we empirically identify that collective reflection results from coping with different types of surprises: communicative platforms are established or further developed over time as a reaction to surprise. Second, we show how coordinating mechanisms allow collective reflection to travel through time and space in organizing. These insights complement and extend existing theory on collective reflection in organizations in three important aspects: we explain and illustrate the emergence of collective reflection as a practice, we propose and illustrate collective reflection as active communicative structuring and as a knotted net of activities. We conclude by discussing boundary conditions, future research and practical implications.