You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How can I oblige you?

USER:  I am David Brown want to cancel my reservation owing an emergency. Can you please help me in cancelling?

ASSISTANT: Sure, please be on hold.

USER: Ok.

ASSISTANT: Sorry, there is no reservation found in your name to cancel.

USER: Thank you for your help.

ASSISTANT: Thanks for approaching us, hope to serve you again.