generate response: I need 4 tickets. What is the reference number?. Intent: book_train. Slots: train-bookpeople=4, train-day=friday, train-departure=peterborough, train-destination=cambridge, train-leaveat=09:00
Response: Booking was successful, the total fee is 66 GBP payable at the station . Reference number is : MU3UYQCK .