generate response: I don't care about departure time, but I need to arrive by 10:15. Intent: find_train. Slots: train-arriveby=10:15, train-day=tuesday, train-departure=london liverpool street, train-leaveat=dontcare
Response: There is a train departing at 07:39 and arriving by 09:07 that fits your needs. Would you like me to book it for you?