One of the most promising computational approaches to representing context in natural language systems has been based on work in general problem solving. In this approach, plans are used both to represent the domain of discourse as well as the communication process itself. Using a simplified framework for planning and action reasoning, we describe techniques that allow systems to handle many dialogues that are problematic for other systems, including the use of sentence fragments, indirect speech, helpful responses, the tracking of the topic of conversations both with and without interrupting subdialogues, and topic change.