You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. What kind of help you need from us now?

USER: I am Scott Taylor. I want to book a flight ticket from HOU to DCA. Could you help me in booking?

ASSISTANT: Sure, Is there any restriction on your ticket fare?

USER: My price limit is 1000.

ASSISTANT: Ok, Help me with your travelling dates as scheduled before?

USER: My preferable dates are from 03/21 to 03/23.

ASSISTANT: Sorry Scott Taylor, there are no flights found at this moment for your journey.

USER: That's ok, no problem. Thank you.

ASSISTANT: Thanks for choosing us, have a great day.