I want to book a train to stevenage, and I want to leave around 14:00.
{"__type": "Inform", "entity": {"__type": "Train", "choice": "several", "destination": "stevenage"}} {"__type": "Request", "service": "train", "values": ["arrive by", "departure"]}
I have several train going to stevenage. Where are you departing from and what time would you like to arrive by?