Hello.
user
Hello. How may I assist you?
assistant
I want to change my existing reservation. Could you help me with that?
user
Sure, I will help you.
assistant
Thank you.
user
May I know your name?
assistant
Amy Wilson here.
user
Please, wait for a while.
assistant
Ok.
user
Thanks for waiting. I am sorry to inform you that, there is no reservation found  on your name.
assistant
That's ok, no problem. Thank you.
user
Thank you for approaching us.
assistant