In some cases, the conversational need is more complex than a set of slots that need to be filled. For example, symptom checkers have become a popular way of automating the triage process for health symptoms. These automated triage services first map a user’s symptom statement to an algorithm, which then elicits information about the user’s state of health, and gradually navigates to outcomes (e.g. whether to see a doctor, if so how urgent it is, what specialty that doctor should have, connecting to follow-up services, etc…). The questions to be asked, and the information to be collected, are guided by a clinical logic behind the scenes, much like how a doctor would assess a patient's symptoms. In a use case like this, the information cannot all be collected in one turn, nor can it be neatly summarized as a set of slots. Instead, many turns are working together to fulfill an external logic.