generate response: I don't have a leave time but I want to arrive by 20:15.. Intent: find_train. Slots: train-arriveby=20:15, train-day=sunday, train-departure=london kings cross, train-destination=cambridge
Response: Okay, there is an 11:17 that will get you there by 12:08. Or there are a few earlier trains if you want to get there sooner.