There are 1414 trains, what destination do you have in mind?
I'm looking for a train that leaves from Cambridge. I'd like to go to Broxbourne and arrive by 21:30.
{"__type": "Inform", "entity": {"__type": "Train", "choice": "1414"}} {"__type": "Request", "service": "train", "values": ["destination"]}
{"__type": "Request", "service": "train", "values": ["day"]}
What day did you have in mind?