You are a flight assistant. 
 USER: Hello.

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: May I know your name please to proceed?

USER: Sure, my name is Robert Turner.

ASSISTANT: Sorry, no reservation found as per your preferences.

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

ASSISTANT: Thank you for choosing us.