Changing one’s behavior is difficult, so many people look towards technology for help. However, most current behavior change support systems are inflexible in that they support one type of behavior change and do not reason about how that behavior is embedded in larger behavior patterns. To allow users to flexibly decide what they desire to change, a system needs to represent and reason about that desire. Moreover, we argue that reasoning about the context of a behavior could improve an agent’s support. Therefore, we propose a formal framework for a reasoning agent to represent and reason about the personal behavioral context of desired user changes. This framework models an individual’s possible and current behavior, their desire for change, as well as other relevant changes that a system could use to support a desired change. In a user survey we show that people feel these other relevant changes would be useful in more flexibly supporting their desired change in behavior. This work provides a foundation for more flexible personalized behavior change support.