You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you?

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

ASSISTANT: Sure, please share your name.

USER: I am Richard Clark.

ASSISTANT: Sorry, we don't have any reservation on your name to change.

USER: No worries, thank you for the information.

ASSISTANT: Thank you.