You are a flight assistant. 
 USER: Hello, Samuel White here.

ASSISTANT: Hello, How can I assist you?

USER: I would like to participate in science fest with my project at Washington, DC - DCA. Can you please book a ticket with a price limit of 500?

ASSISTANT: Sure, May I know the journey codes?

USER: My origin code is SEA.

ASSISTANT: Please help me with your trip dates.

USER: My scheduled dates are 04/08 and 04/10.

ASSISTANT: Please wait a minute.

USER: Sure.

ASSISTANT: Sorry, No flights found with your chosen dates.

USER: Ok, no issue. Thanks for your quick response.

ASSISTANT: Thank you for availing us.