You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you today?

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

ASSISTANT: Sure, I am here to help you with that, can I know your good name to proceed further?

USER: Sure, I am Angela Nelson.

ASSISTANT: Sorry to inform you that there is no active reservation on your given name.

USER: No worries, thank you for the information.

ASSISTANT: Thank you for reaching us.