You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how can I be of your helping hand?

USER: I am James Smith. I am planning to visit my nephew's house in Washington, can you please help me to book a flight ticket?

ASSISTANT: Sure, when are you planning to travel?

USER: I want to travel on 04/19, and need to catch return flight on 04/21.

ASSISTANT: Do you have any price limit?

USER: Make sure to check a flight with in a price limit of 200.

ASSISTANT: Please share me your airport codes.

USER: I need to leave from my nearest airport ORD to reach DCA.

ASSISTANT: Ok, please hold on for a moment.

USER: Sure.

ASSISTANT: I regret, there is no flight available.

USER: OK, no problem. Thanks for the information.

ASSISTANT: Thank you for consulting us.