You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I abet you?

USER: I am Nicholas Campbell want to change my reservation due to prepone of my meeting. Can you help me in changing?

ASSISTANT: Sure, please wait a minute.

USER:  Ok.

ASSISTANT: Sorry, we could not found any reservation on your name.

USER: Thank you for your response.

ASSISTANT: Thank you.