Arianna: Hello. I am sorry but I seem to have lost my confirmation email, and with it my reference number. Any chance you could resend this? 
Robert: Hello, no problem. Where did you book to go and under what name?
Arianna: I have booked the 4.35 coach to Birmingham, under A. Banssa.
Robert: Just a moment please. 
Robert: Please find attached a confirmation of your booking. You will need to show this to the driver when getting on the bus.
Robert: <file_other>
Arianna: That's great thank you
Robert: No worries, enjoy your trip.  
Arianna will need to show the booking confirmation to the driver.