You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you?

USER: I am Robert Williams. I need to cancel my reservation due to sudden change of my plan of going to an historical tour. Can you help me out with cancellation?

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

USER: Thank you.

ASSISTANT: Please give me a moment.

USER: Sure.

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

USER: Ok fine, thanks for your response.

ASSISTANT: Welcome, have a nice day. Thank you for choosing us.