You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello. How may I help you now?

USER: I am Kenneth Lopez, I want to change my existing reservation because my client meeting got delayed.

ASSISTANT: Ok, I can help you for that. Just a minute, I will check and change it.

USER: Ok.

ASSISTANT: Sorry to say this, we did not find any reservation on your name to change it. Thank you for reaching us, have a nice day.

USER: Thank you for your kind information.