generate response: Could you please make a reservation on Sunday for 7 people at 21:00? I would like a reference number.. Intent: book_train. Slots: restaurant-bookday=sunday, restaurant-bookpeople=7, restaurant-booktime=21:00, restaurant-name=charlie chan, train-bookpeople=1, train-day=sunday, train-departure=london liverpool street, train-destination=cambridge, train-leaveat=14:45
Response: Unfortunately, the restaurant is already booked at that time. Is there another day or time you would like to go?