Task-oriented dialogue about: train

I'm looking for a train please.
There are several trains where are you going?
I am going to Cambridge from Leicester. I am planning to leave on Sunday and I need to be there by 11:45.
If you take the TR1079 at 9:09 you can arrive in Cambridge by 10:54. Would you like me to book it?
Yes, that sounds great. I would like to book the train for 7 people. What is the reference number?
there is the reference number TR4106
Thank you for your help
Thank you for using our services. Do you need any further assistance?
That is all I needed. Thank you.
You're welcome. Have a nice day and please call us again!
Wait, I don't think that's a valid reference number.
35VBB0LK if your reference numbers, what else may I help you with?
Great. Nothing else. Thanks, again. Goodbye for now.
most welcome and safe journey