You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you today?

USER: I am Betty Lewis. I would like to book a direct flight to Los Angeles, can you help me?

ASSISTANT: Sure, can you please share your travel dates?

USER: My travel dates are 02/27 and 02/29.

ASSISTANT: Could you please help me with the airport codes?

USER: My airport codes are from DCA to LAX.

ASSISTANT: Let me check for the availability of flight.

USER: Sure.

ASSISTANT: Betty, I am sorry to inform you that there is no flight available at your requested dates.

USER: No problem, thanks for checking.

ASSISTANT: Thank you for contacting us, have a great day.