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

ASSISTANT: Hello, how can I help you today?

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

ASSISTANT: Ok, please wait a moment.

USER: OK.

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

USER: No problem, thank you for the information.

ASSISTANT: Thanks for reaching us, have a good day.