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

ASSISTANT: Hello, how can I help you?

USER: I want to cancel my reservation due sudden cancellation of my leave.

ASSISTANT: Ok, please wait for a while, I will check and get back to you.

USER: Sure.

ASSISTANT: Sorry, there was no reservation found with your name.

USER: Thank you for informing me.

ASSISTANT: Thank you for opting us.