You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you?

USER: I want to change my reservation, can you help me?

ASSISTANT: Yes, I can help you. Can I know your name for checking your previous reservation?

USER: Myself Nicholas Green.

ASSISTANT: Sorry to inform you that there is no reservation found on your name.

USER: No problem, thanks for checking.

ASSISTANT: Thank you for reaching us.