generate response: I want to book a table for 5 people at 13:00 on saturday.. Intent: book_restaurant. Slots: restaurant-area=centre, restaurant-bookday=saturday, restaurant-bookpeople=5, restaurant-booktime=13:00, restaurant-food=north american, restaurant-name=gourmet burger kitchen
Response: Unfortunately, they are all full at that time. Would you like me to try another restaurant?