Hello.
Hello, how may I serve you at this moment?
Is this Central travel agency? Yesterday I booked a ticket to New York through your agency, your agent  by mistakenly booked a ticket  on wrong dates, so I want to change my reservation.
Ok, sure I can search with your ticket reservation.Can I know your name?
I booked a ticket on the name of Margaret Lee.
Sorry for the inconvenience, no reservation found on your name in my database.
That's fine, I will try for other agency.
Thank you for reaching us.