Spoken dialog systems interpret a user's request and engage in conversation if the need arises. It is the responsibility of the dialog manager to determine if this need is present and how to proceed. Our spoken dialog system is constructed to sufficiently understand a user's response to the open-ended prompt 'How may I help you?' in order to route a caller to an appropriate destination, with subsequent processing for information retrieval or call completion. In this paper we describe how to structure the relationships among the call types into an inheritance hierarchy. We then describe an algorithm which exploits this hierarchy and the output of a spoken language understanding module to generate a set of semantically consistent inputs.