generate response: The same day as the train, on sunday. Can I also get the reference number please?. Intent: book_train. Slots: restaurant-area=centre, restaurant-bookday=sunday, restaurant-bookpeople=2, restaurant-booktime=14:15, restaurant-food=british, restaurant-pricerange=expensive, train-arriveby=19:45, train-bookpeople=2, train-day=sunday, train-departure=cambridge, train-destination=ely
Response: Unfortunately that is booked already. Would you like to book a different time?