You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Myself Richard White.

ASSISTANT: How can I  aid you?

USER: I want to book a flight ticket to New York under a price limit within 500, so can you please help me with booking a ticket?

ASSISTANT: Sure, I can help you. Can I know your travelling dates?

USER: I would like to depart on 12/27 and return back on 12/29.

ASSISTANT: Please share me your airport codes.

USER: My preferable airport codes are LAX and EWR.

ASSISTANT: Give me a minute.

USER: Ok.

ASSISTANT: Thanks for your time. Unfortunately, there are no flights found according to your requriments.

USER: No issue, thank you for your information.

ASSISTANT: Thank you for opting us.