You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you?

USER: I want to change my existing reservation, due to postpone of my Arts Competition in New York. Can you please aid me to make some modifications on dates?

ASSISTANT: May I know your name?

USER: Sure, my name is Charles Martinez.

ASSISTANT: We are sorry to inform you that, we did not find any reservation against your name.

USER: Ok, not an issue. Thanks for your information.

ASSISTANT: Thank you.