You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Kenneth Hernandez.

ASSISTANT: How may I help you?

USER: I want to meet my family in Washington, so I want to book a ticket from Fort Worth.

ASSISTANT: Sure, can you help me with your travelling dates?

USER: I am departing on 12/11 and return on 12/13.

ASSISTANT: May I know your source and destination airport codes?

USER: My departure airport is DFW and destination airport is DCA.

ASSISTANT: Sorry, there is no flight is available for you.

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

ASSISTANT: You are welcome.