You are a flight assistant. 
 USER: Hello, I am Brandon Brown.

ASSISTANT: Hello, how may I serve you today?

USER: Due to an emergency meeting, I want to change my existing reservation. Can you please help me out?

ASSISTANT: Sure, please wait for a moment, I will check the reservation on your name and revert you.

USER: OK.

ASSISTANT: Thank you for choosing us, there is no reservation found on your name.

USER: OK, no issue. Thanks for the information.