hi , can you help me find a train departing from cambridge ?
user
what is your destination ?
assistant
i am going to leicester
user
it looks like trains run along that route every hour . is there a certain day and time you would like to know about ?
assistant
i would like to leave after 20:15 .
user
there are 28 trains that leave after 20:15 , what time would you like to arrive by or does it matter ?
assistant
no , the arrival time does not matter . i need to book 4 tickets .