Exploratory search is a difficult activity that requires iterative interaction. This iterative process helps the searcher to understand and to refine the information need. It also generates a rich set of data that can be used effectively to reflect on what has been found (and found useful). In this paper, we describe a framework for unifying transitions among various stages of exploratory search, and show how context from one stage can be applied to the next. The framework can be used both to describe existing information-seeking interactions, and as a means of generating novel ones. We illustrate the framework with examples from a session-based exploratory search system prototype that we have built.