Hi. I am Justin Brown.
Hello, How can I provide assistance to you?
As my appointment with doctor got postponed, I want to change my reservation.
Ok.
Can you help  me with it please?
Sure, I will help you. Please wait for a while, I will revert to you.
Thank you, take your time.
Thanks for waiting, but sorry to inform you that no reservation is existed on your name.
That's fine, thank you for the response.
Thank you for reaching us, Have a nice day.