i am looking for a train to cambridge .
user
when will you be travelling ?
assistant
i'll be leaving friday after 20:45 .
user
i have several options for you depending on your departure site . where will you be leaving from ?
assistant
i need to depart from cabridge and go to bishops stortford .
user
there are few options to choose from . how many people are traveling ?
assistant
i will have 2 people traveling .
user
okay , would you like me to book tr4664 ?
assistant
yes , please . i need the reference number .