This article presents findings from an innovation research project titled School-In, focusing on school staff's reflection. Teachers in four schools participated in focus group discussions in the beginning and at the end of the innovation. Wackerhausen's theory is used to understand reflection and how it develops in professional learning communities. Findings from the study indicate: (1) in the beginning of the innovation, reflection mainly of first order -- focusing on how things are or should have been; and (2) at the end of the innovation, reflection mainly of second order -- critical reflection on the school's practices. Change is promoted by use of different reflective work forms in mixed groups, focusing on collective capacity and common expectations. The innovation releases teachers' knowledge and experiences, enabling them to carry out second-order reflection and to critically analyzing their personal and the school's practice.