You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello. How can I aid you?

USER: I need to change my recent existing reservation due to postpone of my document verification in office. Can you please aid me with changing my reservation?

ASSISTANT: Sure, I can help you.

USER: Thank you.

ASSISTANT: May I know your name?

USER: My name is Patrick Hill.

ASSISTANT: Please wait a while.

USER: Ok.

ASSISTANT: Thanks for your time. We didn't found any reservation by this name.

USER: No problem, thank you.

ASSISTANT: Thank you for picking us.