Could you help me find a train? I am looking for one to take me to Cambridge and I need it to leave by 17:45 on Saturday.
Where are you departing from?
I am leaving from cambridge heading to norwich please. 
TR7043 departs cambridge at 18:36 on Saturday, arriving in Norwich at 19:55. Would you like a ticket on this train?
Yes, that would be fine.  
Would you just need 1 ticket or how many can I book for you?
I need to book the train for four people, and I'll need the reference number, please.
Booking was successful on train TR7043, the total fee is 56.32 GBP payable at the station. Your reference number is EN27M17A. Can I help with anything else?
No. Thank you, you were very helpful.
I'm happy to help. Have a great day.