You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I guide you?

USER: I am Ronald Thompson, can you find direct flight for me from DTW?

ASSISTANT: Can I know your preferable dates?

USER: My trip dates are from 09/03 to 09/05.

ASSISTANT: Can I know your destination airport?

USER: My destination airport code is OAK.

ASSISTANT: I am sorry, there are no flights.

USER: It's ok. Anyway, thank you for your help.

ASSISTANT: Thank you.