You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how may I serve you?

USER: I am John Anderson, my business meeting was postponed so I want to change my recent reservation.

ASSISTANT: Ok, please wait I will check your reservation and change it accordingly.

USER: Ok.

ASSISTANT: Sorry, we did not find any reservation on your name. Thanks for contacting us, have a nice day.

USER: Thank you, for your quick response.