You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you?

USER:  I am Donald Anderson.

ASSISTANT: Ok.

USER: I want to change my reservation due to prepone of my meeting. Can you help me with it?

ASSISTANT: Sure, I will help you. Please, standby.

USER: Ok.

ASSISTANT: Thanks for waiting. We could not find any reservation on your name.

USER: Thank you for your help.

ASSISTANT: Thank you for approaching us.