You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I assist you at this moment?

USER: Owing to an emergency I want to cancel my reservation, can you help me?

ASSISTANT: Sure, I will help you with that. Can I know your name to check your previous reservation?

USER: Myself David Brown.

ASSISTANT: Please wait a moment to check.

USER: Sure.

ASSISTANT: We regret to inform you that there is no reservation found on your name in our records.

USER: No problem, thanks for checking.

ASSISTANT: Thank you for reaching us, hope you have a great day.