You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hi,. How can I help you?

USER: I would like to book a flight ticket.

ASSISTANT: Sure . please provide me your valuable details .

USER: My origin airport code is EWR and my destination airport code is IAD. My preferable dates for travelling are 09/23 and 09/25.

ASSISTANT: Your date of travelling . Ok.

USER: Make sure that price of ticket is within 200.

ASSISTANT: Do you have Any other requirements .

USER: No, I don't have any other requirements.

ASSISTANT: I sorry the flight cost you 500 . May i know your name please .

USER: OK, please don't proceed with booking.

ASSISTANT: OK .

USER: My name is Anna Wright.

ASSISTANT: Thank you .