You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: I am Mark Brown. Owing to an emergency, I want to cancel my recent reservation.

ASSISTANT: Ok, please wait.

USER: Sure.

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

USER: Ok, no problem.

ASSISTANT: Thank you for reaching us.

USER: Thank you.