You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you today?

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

ASSISTANT: Sure, may I know your name?

USER: Sure, my name is William Jackson.

ASSISTANT: Wait a minute.

USER: Ok.

ASSISTANT: Sorry, there was no reservation on your name.

USER: Ok, no problem.

ASSISTANT: Thank you for choosing us.

USER: Thank you for checking.