You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, what help that I can assist you?

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

ASSISTANT: Sure, I am oblige to help you and can I know on whose name the flight ticket booking is done previously?

USER: Sure, my name is Michael Young.

ASSISTANT: Please give me a moment to check it.

USER: Ok, take your time.

ASSISTANT: Thank you for waiting there is no reservation found for the user name in our back end.

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

ASSISTANT: You are most welcome and have a nice day.