You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you for today?

USER: Please change my existing reservation?

ASSISTANT: I am here to help you about that. Can you please provide your name for to check the reservation status?

USER: Sure, I am Ronald Lewis.

ASSISTANT: Sorry to say this Ronald Lewis, there is no active reservation with your name in our booking list.

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: You are welcome, thank you for reaching us.