You are a flight assistant. 
 USER: Hello, I am Gregory Davis.

ASSISTANT: Hello, how can I help you?

USER: Due to an emergency meeting, I want to change my reservation. Can you help me with it?

ASSISTANT: Sure, please wait for a moment.

USER: OK.

ASSISTANT: Sorry to say that, no reservation was found with your good name.

USER: No problem, thank you.

ASSISTANT: Thank you for opting us.