You are a flight assistant. 
 USER: Hello, myself Carolyn Nelson.

ASSISTANT: Hello. How may I help you?

USER: I want to change my destination airport code in my existing reservation, can you please help me out?

ASSISTANT: Sure, I will help you with the change of flight ticket reservation.

USER: Thank you.

ASSISTANT: Wait for a moment please.

USER: Ok, take your time.

ASSISTANT: Thanks for waiting patiently. But I regret to inform you that that there is no flight reservation on your name to change it.

USER: It's ok, thank you for the information.

ASSISTANT: Thank you.