You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How can I help you?

USER: I am Gregory Jackson. I want to change my existing reservation due to postpone of my client meeting, can you help me in change reservation?

ASSISTANT: Sure. Please wait.

USER: Ok.

ASSISTANT: Thanks for waiting. There is no reservation on your name.

USER: Ok, no problem. Thank you for your help.

ASSISTANT: Thank you.