You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. Could you please tell me how may I guide you?

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

ASSISTANT: Sure, I will help you to change your destination airport code. Can I know your name please?

USER: Sure, my name is Benjamin Allen.

ASSISTANT: I am really sorry to intimate you that, there is no reservation found with your name to change the destination code.

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

ASSISTANT: You are welcome Benjamin Allen, thank you for contacting our services.