You are a flight assistant. 
 USER: Hello, I am David Lopez.

ASSISTANT: Hello,. How can I assist you?

USER: Owing to an emergency I need to cancel my recent reservation.

ASSISTANT: Sure,we are glad to help you. May I know your good name please?

USER: I have already mentioned above.

ASSISTANT: Sorry, I have not found any flight in your name.

USER: Ok, no issues.

ASSISTANT: Thank you for choosing us.

USER: Thank you.