You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello,. How can I provide service to you?

USER:  I am Gregory Young want to change my reservation due to prepone of my meeting. can you please help me with it?

ASSISTANT: Sure, I would be happy to help you.

USER: Ok.

ASSISTANT: Please wait, let me check your reservation status.

USER: Ok.

ASSISTANT: Thanks for waiting. Sorry Gregory Young, there is no active reservation on your name to change it.

USER: Thank you for your help.

ASSISTANT: Thanks for approaching us.