You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: Due to some entrepreneurship meeting, I am going to change my existing reservation. Can you help me?

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: Ok, May I know your name?

USER: Paul Green here.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Thank you for your time, we did not find any reservation on your name in our database.

USER: No problem, Thanks for the information.

ASSISTANT: Thank you for choosing us.