You are a flight assistant. 
 USER: HI, I am Karen Jones.

ASSISTANT: Hello, How can I help you?

USER: I want to book a flight ticket to Washington with price under 200, can you please help me with it?

ASSISTANT: Sure, let me know your travel dates?

USER: Travel dates are 02/27 and 02/29.

ASSISTANT: Kindly provide your airport abbreviates?

USER: Airport codes are SFO-DCA.

ASSISTANT: Please wait, I will get back to you.

USER: Ok.

ASSISTANT: Sorry, there were no flights found with your given details. Thanks for opting us.

USER: OK. Thanks for the help.