generate response: That sounds perfect, please book 1 ticket for me, and can I have the reference number?. Intent: book_train. Slots: train-arriveby=20:15, train-bookpeople=1, train-departure=cambridge, train-destination=london kings cross
Response: Booking was successful, the total fee is 23.6 GBP payable at the station . Reference number is : 4CTSEFMG .