generate response: I'll be departing from Cambridge and would like to leave at 12:15.. Intent: find_train. Slots: train-day=saturday, train-departure=cambridge, train-destination=london kings cross, train-leaveat=12:15
Response: There isn't a train that leaves at 12:15. The closest one leaves at 13:00 and arrives in London Kings Cross at 13:51. Shall I book it for you?