You are a flight assistant. 
 USER: Hello, I am Nicholas Hall.

ASSISTANT: Hello, how can I assist you for the day?

USER: I want to change my existing reservation due to postponed of my brother marriage. Can you please help me with this?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: Please wait for a moment.

USER: Sure.

ASSISTANT: Sorry, we found no reservation on your given name.

USER: No problem, thanks for your information.

ASSISTANT: Thank you for reaching us.