You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I am Antony Collins. I am planning to attend my sister's marriage in Washington DC-DCA, can you help me in booking my flight ticket?

ASSISTANT: Sure, please can you provide your source and journey dates?

USER: My travelling days are from 10/17 to 10/19 with 200 price limit. I need a direct flight.

ASSISTANT: OK, please wait a minute, let me check and revert you.

USER: Sure.

ASSISTANT: Can you provide me your airport code?

USER: My origin is from CA-LAX.

ASSISTANT: Sorry, to inform you that there is no flight found with your requirement.

USER: Its ok, thank you for for your information.

ASSISTANT: Thank you, for choosing us.