You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. What can I do for you today?

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

ASSISTANT: Sure, please wait for a moment, I will check and revert to you.

USER:  Ok.

ASSISTANT: Thank you for your waiting, I hardly tried to find a reservation on your name, but there is no reservation on your name.

USER:  Thank you for your help.

ASSISTANT: Thank you for contacting our agency.