i need to catch a train on thursday , departing from birmingham new street .
user
okay and what is your destination please ?
assistant
i am travelling to cambridge .
user
please specify your choice of time for departure and arrival
assistant
i need to leave after 14:45 .
user
what time do you need to arrive by ?
assistant
i do not have an arrival preference .
user
i have the tr2148 that leaves at 15:40 for 75.10 pounds . would you like to book it ?
assistant
yes i need 6 tickets and the reference number .