Query: user: I would like to find a train.
assistant: Where are you departing from and what is your destination?
user: I'm leaving Washington to Chicago on March 6th.
assistant: There are 5 trains. There is one leaving at 9:40 am for $109.
user: Which station does it leave from?
assistant: The train leaves from Union Station.
user: I would like to purchase tickets.

Intent: Trains:GetTrainTickets