Task-oriented dialogue about: train

I need a train that leaves this Thursday from Cambridge to Ely.
I have 10 trains to Ely Thursday, leaving on the :50 every two hours from 05:50 to 23:50. Did you have a particular time in mind?
I need to leave after 17:45 so anytime after that would be great.
I have train TR7355 from Cambridge departing at 17:50 and arriving in Ely at 18:07. Would this train work for you or would you like a later departure?
That's great. I'll need 3 tickets, please.
Booking was successful, the total fee is 13.2 GBP payable at the station. Reference number is : WDETDX35 .
I apologize this train is going to broxbourne from cambridge. for 3 people are you able to book that?
Sure, do you still need the train on Thursday after 17:45?
Yes, that's Broxbourne to Cambridge on Thursday, leaving after 17:45.
When would you like to arrive?
Sorry. I really need to be leaving from Cambridge to go to Broxbourne, leaving after 17:45 on Thursday. Arrival time doesn't matter.
How about TR9890? It departs Cambridge at 18:01 and arrives in Broxbourne at 19:01. It is 17.90 pounds per ticket. Would you like to book that one?
Yes, please. I will need the reference number when you are finished.
Your booking was a success. The total fee for 3 tickets is 53.70 GBP, payable at the station, and your reference number is TSUJXVYU . Is there anything else I can do?
No that will do , cheers.
Thank you, good bye.