Hello, I'd like some information on a train going to cambridge.
Sure! Where are you departing from?
I am leaving Stevenage on Thursday and I want to arrive by 10:15. 
I have a train on Saturday that leaves Cambridge on Saturday at 07:54 and arrives at 08:43.
I need the train Thursday 
There is one leaving at 5:54,Yes I will book it for you and provide a reference number