You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I'm Donna Thompson I want to change my existing reservation.

ASSISTANT: OK.

USER: Can you help me on it?

ASSISTANT: Give me a moment.

USER: OK.

ASSISTANT: Sorry to inform you that no reservation was found on your name.

USER: OK. Not an issue. Thank you for your service.