You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Charles Williams.

ASSISTANT: How can I help you?

USER: Owing an emergency, I want to cancel my recent reservation. Can you please help me?

ASSISTANT: Sure, I will help you to cancel your reservation.

USER: Thank you.

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

USER: That's ok, thank you for your information.

ASSISTANT: Welcome, have a  nice day.