You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you today?

USER: Due to inconvenience of my work, I want to change my reservation. Can you please help me for that?

ASSISTANT: Sure, I am glad to help you.

USER: Thanks.

ASSISTANT: May I know your name please?

USER: I am William Hall.

ASSISTANT: Thanks for your name, please wait.

USER: Ok.

ASSISTANT: Thank you for waiting, no reservation was found on your name to change.

USER: Anyway, thanks for the information.

ASSISTANT: Thank you for availing us.