You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you now?

USER: I am Donald Campbell. I want to change my existing reservation due to sudden rainfall at my source. Can you please help me with this?

ASSISTANT: Sure Donald Campbell, I am happy to help you with that.

USER: Thank you.

ASSISTANT: Please wait a moment to check your reservation status.

USER: Sure.

ASSISTANT: Sorry Donald Campbell, no reservation has found under your name to change.

USER: Ok, not an issue. Thank you for checking.

ASSISTANT: Thank you for choosing us, have a good day.