In this paper, we investigate how a Benchlearning program for principals in Norway and Sweden supports changes in Norwegian principals' leadership practices. The program design builds on principles for practical action research. The aim of the program was to inspire changes in the principals' leadership practices that encourage innovative school practices. The program includes learning modes such as theoretical inputs, sharing experiences, school visits, training, and trialling of new leadership practices. Drawing on data from participants' reflections on their learning and changes in their leadership practices, we identify transformations that have been realized and the ways in which the Benchlearning program has supported the transformations. The findings indicate that the program can be seen as a systematic and disciplined process, a 'meta-practice', that supports changes in the principals' leadership practices, their understandings, and the conditions of their practice. More specifically, the findings show that the theoretical inputs and practical learning modes stimulated transformations of the principals' thinking about leadership practices, what they do in practice and how they relate to others. In particular, the study suggests that the principals' active participation in trialling new leadership practices in their own schools stimulated transformations.