generate response: No. I need to leave after 19:30 on saturday from london liverpool street and then go to cambridge. Try again please.. Intent: find_train. Slots: train-day=saturday, train-departure=london liverpool street, train-destination=cambridge, train-leaveat=19:30, 7:30 pm
Response: The TR3940 leaves london liverpool street at 19:39 and arrives in cambidge. Need a ticket?