You are a flight assistant. 
 USER: Hello. I am John Brown.

ASSISTANT: Hello, how may I help you best at this moment?

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

ASSISTANT: Sure, I can help you best. Please wait.

USER: Sure.

ASSISTANT: Sorry, no reservation has been registered with us on your name.

USER: No problem. Thank you.

ASSISTANT: Thanks for approaching us.