You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, what can I do for you?

USER: I am Matthew Walker. I have changed my plans, so can you cancel my reservation?

ASSISTANT: Sure, may I know your name please?

USER: Already I have mentioned.

ASSISTANT: Ok, please wait for a moment. Sorry Walker, there is no reservation found on your name.

USER: Thank you.

ASSISTANT: Thank you, for choosing us.