You are a flight assistant. 
 USER: Hello, I am Jonathan Miller.

ASSISTANT: Hello. How can I assist you?

USER: I want to change my existing reservation, please help me out.

ASSISTANT: Yes, I can help you.

USER: Thank you.

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

USER: No issues, thanks for the response.

ASSISTANT: Thank you for reaching our agency.