I need to find a train that arrives at 12:30 on Wednesday. 
Certainly. Could you tell me where you're departing from and traveling to?
I am departing from Birmingham new street and going to Cambridge. 
I have seven trains available then, could you tell me what time you would like to leave ?
Yes I need to arrive in Cambridge by 12:30 please.
The TR3543 puts you into Cambridge at 12:23. Will that train work for you?
Yes, that will work. Can you book that train for 8 people? I will also need a reference number.
Certainly. I have you booked and your reference number is 47MBURBC.
Great! Thanks, that's all I need. 
Thank you! Have a great day!
Thank you for all of your help!
Have a great day!