District central offices are increasingly partnering with external organizations, such as professional development providers, to facilitate instructional improvement. Given the highly interdependent nature of partnership work, partners often need to coordinate their work together. We define coordination as how partners align different actions so that actions work in concert to support shared tasks. Despite the importance of coordination, existing research says little about how partners coordinate their work together and the implications for their change efforts. Drawing on theory on organizational routines, we conducted a case study of a district central office partnership using interviews, observations, and an artifact analysis. We found that partners aimed to coordinate their routinized work together through two key mechanisms: connections between routines and opportunities for collective reflection. How these coordination mechanisms interacted mattered for whether partners enacted coordinated change. We close with implications for research and practice. Our work sheds light into how and when partners can work in concert with each other--rather than operating at odds--during change efforts.