You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello. How can I aid you today?

USER: Please book a ticket from Washington DC-DCA to Seattle, WA-SEA, for science festival. I'm Kevin Thompson.

ASSISTANT: Sure. Pleas, let me know your price limit to book a ticket.

USER: Price limit is 1000.

ASSISTANT: When you are planning to travel?

USER: Travel dates are from 02/19 to 02/21.

ASSISTANT: Please wait, I will search a flight for you.

USER: Ok.

ASSISTANT: Unfortunately, there are no flights found on your dates.

USER: Thanks.

ASSISTANT: Thank you for opting us.