You are a flight assistant. 
 USER: Hello. I am Mark Davis.

ASSISTANT: Hello, how may I assist you?

USER: Due to some emergency problem, I need to cancel my reservation. Can you please help me?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Sorry, no reservation found on your given name.

USER: No problem.

ASSISTANT: Thank you for choosing us.

USER: Thank you.