Despite having significant knowledge of effective practices, along with curricular and pedagogical resources, efforts to transform introductory sequences have met with only modest success. While educators may know what to do, they do not know how to enact and sustain these reforms at scale. What they need is a framework for understanding STEM instructional "change". In this article, the authors propose such a framework to provide a tool for those engaged in educational transformation at the undergraduate level, particularly within STEM education. They summarize findings from an interdisciplinary literature review, introduce a typology of change strategies, and use these to make recommendations for mechanisms of change. (Contains 1 figure and 8 resources.)