You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you today?

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

ASSISTANT: Sure, may I know your name for the changing process?

USER: Sure, my name is Margaret Roberts.

ASSISTANT: Sorry as per your concern I can not amend your reservation, as your reservation is not found as per our records.

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

ASSISTANT: Welcome, thank you for reaching us.