You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I am Donna Nelson want to change my reservation due to prepone of my meeting.

ASSISTANT: Sure, I will help you to change your reservation. Please wait for a moment.

USER: Ok.

ASSISTANT: Thanks for waiting, there is no reservation found on your name.

USER: Thanks for your help.

ASSISTANT: Thank you for reaching us, have a nice day.