You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

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

ASSISTANT: Sure, may I know your good name?

USER: I am Jennifer Williams.

ASSISTANT: Please wait for a moment.

USER: Sure.

ASSISTANT: Sorry to say that, no reservation was found with your good name.

USER: No worries, thank you for the information.

ASSISTANT: Thank you for reaching us.