Lasting change in teacher practice is difficult because it expects that teachers challenge and reconstruct deeply embedded practices and beliefs. Less research has examined teachers' change process to better understand what professional spaces foster teachers as they construct their own transformation. This qualitative study examined the following research question: What was the change process of one teacher researcher as she engaged in a year-long practitioner researcher group? Building on teacher education research that addresses teacher change the author focuses on three central theorists, Dewey, Schon, and Kegan, because of their focus on professional experience and critical reflection. Their theories of change imply that teachers must acquire new knowledge and put that new knowledge into practice to promote learning in their classrooms. The author uses the phrase architect of transformation to highlight elements of practitioner agency and identity shifts that changed how teachers see themselves, their students, and the world around them. This study draws upon case-study research methods and positioning theory to better understand Grace's (a fifth-grade teacher) change process in a practitioner research group for one year. Findings illustrate not only how she transformed but also how members of the group positioned Grace in ways that helped her imagine, prepare, and enact new positions in other environments. This study has several implications for professional development and teacher change. For Grace, change was a dynamic, interactive, and complex experience. (Contains 2 tables.)