You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you today?

USER: I need to change my reservation due to urgent meeting, can you help me?

ASSISTANT: Sure, I am happy to help you in changing your existing reservation. Please, share me your name to check your reservation status.

USER: I am Brian Clark.

ASSISTANT: Ok, please wait for a moment.

USER: Sure.

ASSISTANT: Sorry to inform you that, we have not found any active reservation on your name in our database.

USER: That's ok. Thank you.

ASSISTANT: Thank you for opting us.