You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you today?

USER: I am John Roberts.

ASSISTANT: Ok.

USER: I want to cancel my reservation due to sudden perpone of my paper presentation at my University. Can you help me to cancel my ticket?

ASSISTANT: Sure, please wait for a moment.

USER: Sure.

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

USER: Ok, thank you.

ASSISTANT: Thank you for opting us.