Hi, I am John Hall.
Hello, how can I provide assistance to you?
I have a plan to travel to Chicago for attending a meeting in my head office but that meeting got postponed, so  please consider my request to change my reservation.
Ok, please wait a moment I will check and get back to you.
Sure.
Sorry to say, no reservation found with your name.
Fine, thank you.
Thanks for reaching us, have a good day.