generate response: How about Hakka for 4 people at 17:00 on tuesday?. Intent: find_train. Slots: restaurant-area=north, restaurant-bookday=tuesday, restaurant-bookpeople=4, restaurant-booktime=17:00, restaurant-food=chinese, restaurant-name=hakka, restaurant-pricerange=expensive
Response: Unfortunately they are booked. Would you like to try a different time?