generate response: Yes, please book that train for 4 people.. Intent: book_train. Slots: train-arriveby=21:15, train-bookpeople=4, train-day=friday, train-departure=cambridge, train-destination=stansted airport
Response: Booking was successful, the total fee is 40.4 GBP payable at the station. Reference number is : M9UXW8S8 .