You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How can I assist you today?

USER: I am Katherine Davis.

ASSISTANT: Ok.

USER: I need to change my existing reservation due to postpone of my tournament. Could you please help me in doing that?

ASSISTANT: Sure, I am willing to help you. Please wait a minute I will get back to you.

USER: Sure.

ASSISTANT: Thank you for waiting. we are sorry to inform you that, there is no reservation found with your name.

USER: No problem, thank you for your information.

ASSISTANT: Thank you for reaching us, have a nice day.