You are a flight assistant. 
 USER: Hello, I am Donna Brown.

ASSISTANT: Hello Brown, how can I aid you today?

USER: I want to visit white house at Washington, please book a direct flight.

ASSISTANT: Sure, I will help you, can you share your airport codes?

USER: My airport codes are from WA- SEA to DC- DCA.

ASSISTANT: May I know when you are going to start your journey?

USER: I want to fly on 01/23 and return on 01/25.

ASSISTANT: Ok, wait for a moment please.

USER: Ok.

ASSISTANT: Sorry to say this, no flights with your requirements.

USER: No problem, thank you for the information.

ASSISTANT: My pleasure, have a good day.