You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may 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, I will help you in that. Can I know your name please?

USER: I am Jeffrey Miller.

ASSISTANT: Sorry Jeffrey Miller, there is no active reservation on your name.

USER: No worries, thank you for the information.

ASSISTANT: Thank you.