generate response: book for 5 people and get me reference number. Intent: book_train. Slots: train-bookpeople=5, train-day=saturday, train-departure=bishops stortford, train-destination=cambridge, train-leaveat=20:45
Response: Okay, great. Your booking was successful! Your reference number is ML7ZBHM1 . Your total fee is 40.4 GBP which can be paid at the station.