You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I assist you at this moment?

USER: I would like to travel from Dallas & Fort Worth to Washington in order to attend a wedding. Can you help me book a flight ticket within the price of 200?

ASSISTANT: Based on your request I am ready to help you but I need your travel dates to search best available flight for you.

USER: I planned my dates of journey to be on 02/10 and 02/12.

ASSISTANT: Can you share your travel from Dallas & Fort Worth to Washington airport codes?

USER: They are from DFW to IAD.

ASSISTANT: Please wait for a minute, let me check.

USER: Sure.

ASSISTANT: May I know your name to proceed further?

USER: Susan Harris is my name.

ASSISTANT: Sorry, I could not find any flight with your detail, do you want any other help.

USER: No. Thank you for the response.

ASSISTANT: That's fine. Welcome.