Hi, I'm looking to book a ticket for a train departing on Sunday from Cambridge please?
What is your destination? 
I want to arrive at London Kings Cross.
What time would you like to leave by?  It is a 51 minute trip for 18.88 pounds.
I don't have a departure time but I want to arrive by 21:30.
There is a train leaving Cambridge on Sunday at 19:00.  It arrives at London Kings Cross at 19:51.  May I book that for you?
No, I just needed the information, thanks.  Have you heard of the Meze Bar Restaurant?
I need more information on the restaurant because my system is not showing me anything on it.