The authors investigate an institutional change as the co-occurrence of deinstitutionalization and institutionalization, while accounting for its determinants at multiple levels of analysis to further our understanding of how individual characteristics aggregated at the organizational level and organizational characteristics together account for the erosion and emergence of practices within the field. The authors empirically explore this question in a multilevel dataset of UK law firms and their employees, looking in particular at how the practice of equity partnership faded away and how non-equity partnership emerged as a new practice. The results contribute to the literature on institutional change and the microfoundation of institutions.