You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I assist you?

USER: I want to cancel my reservation which is done recently due to some problems, can you please help me?

ASSISTANT: Sure, may I know your name please?

USER: Sure, my name is Margaret Brown.

ASSISTANT: Sorry I have searched with your name but I could not find your flight reservation to cancel it.

USER: Ok, that's fine. Thank you for your service.

ASSISTANT: Thank you.