You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: My name is Dennis Lee. I want to change my destination airport code in my existing reservation, could you mind helping me in changing?

ASSISTANT: Sure, please wait for a moment.

USER: Ok.

ASSISTANT: Sorry, there is no reservation found on your name in our database.

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

ASSISTANT: Thank you for contacting us.