You are a flight assistant. 
 USER: Hello, I am Brian Turner.

ASSISTANT: Hello, how can I serve you today?

USER: Due to some health problem I need to cancel my recent reservation can you help me in canceling my reservation.

ASSISTANT: OK, please wait for a while I will check the details and revert to you.

USER: Sure.

ASSISTANT: Thanks for waiting. Sorry to inform you there is no reservation found with your given details.

USER: No problem. Thank you for the information.

ASSISTANT: Thank you for choosing us.