Hi.  Can you please help me find a train to Leicester.  I need to leave on Monday.
Do you want to arrive or leave at a certain time?
Yes, I need to leave sometime after 20:00 from Cambridge.  It doesn't matter when I get there.
Okay TR9424 departs at 20:21. Would you like me to book that for you?
Could you book a trip for five people, and give me the reference number?
I have those seats booked for you. Your reference number is Q0B623JD. You will pay 189 gbp at the station. 
Thank you that's all I needed today. 
You're welcome. Have a great day!