You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: Can you help me to change my reservation?

ASSISTANT: May I know your name please?

USER: I am Charles Wilson.

ASSISTANT: Please wait.

USER: Sure.

ASSISTANT: Sorry, no reservation found on your name to change.

USER: No problem, thank you for checking.

ASSISTANT: Thank you for reaching us.