generate response: I'm so sorry. I need to leave Cambridge after 13:00 on Tuesday and I'm going to Ely. I need 6 tickets.. Intent: book_train. Slots: train-bookpeople=6, train-day=tuesday, train-departure=cambridge, train-destination=ely, train-leaveat=13:00
Response: I booked you for 6 tickets on the 15:50 train that arrives in Ely at 16:07. your reference number for the journey is 3QK3PKJT .