You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you today?

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

ASSISTANT: Sure, we are glad to serve you.

USER: Thanks.

ASSISTANT: Before changing your flight reservation. May I know your name?

USER: Sure, my name is Larry Taylor.

ASSISTANT: Sorry Larry Taylor, we haven't found any previous reservation based on your name.

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

ASSISTANT: Thanks for reaching us.