You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you today?

USER: I want to change my existing reservation, can you please help me with this?

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

USER: My name is Joseph Williams.

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

USER: No problem, thanks for your information.

ASSISTANT: Thank you for reaching us.