You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you?

USER: My name is Kenneth Lopez. I want to change my existing reservation, due to some weather issue. Can you help me for that?

ASSISTANT: Sure, please wait a moment I will check your complete reservation details and proceed further.

USER: Ok.

ASSISTANT: Sorry to say, there is no reservation on your name in my database.

USER: That's ok, thank you for checking.

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

USER: Welcome.