generate response: I would like an early train, yes. As close to 8:30 as possible. I need tickets for 7 people.. Intent: book_train. Slots: train-bookpeople=7, train-day=monday, train-departure=cambridge, train-destination=stansted airport, train-leaveat=08:30
Response: Okay, I got you 7 tickets on the train leaving at 8:40. Your reference number is KVV4HJSU