You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Sarah Harris.

ASSISTANT: How can I aid you at this moment?

USER: I would like to change my existing reservation due to postpone of my comic fair. Could you please help me?

ASSISTANT: Sure, I will help you with that. Please wait a moment.

USER: Ok.

ASSISTANT: There is no previous reservation available in your name.

USER: No problem, than you for the information.

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