You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I serve you at this moment?

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

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: May I know your name please?

USER: Sure, my name is David Harris.

ASSISTANT: Ok, please be on hold.

USER: Ok, take your time.

ASSISTANT: Sorry, we could not find any reservation on your name.

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

ASSISTANT: Thank you for approaching us.