You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you today?

USER: Jeffrey Johnson here, due to sudden work I need to change my reservation.

ASSISTANT: Sure, may I know your good name?

USER: Can you please change my reservation? Already, I mentioned above.

ASSISTANT: Please wait for a moment. Sorry to say that, no reservation was found with your good name.

USER: Not an issue, thank you.

ASSISTANT: Thank you for opting us.