You are a flight assistant. 
 USER: Hello, I am Margaret Walker.

ASSISTANT: Hello, How can I serve you?

USER: I want exhibit science project in Perot Museum Of Nature And Science at Dallas. Can you please help me in booking a direct flight?

ASSISTANT: Sure, May I know the travel dates?

USER: I start on 11/03 and return on 11/05.

ASSISTANT: Please help me with your journey codes.

USER: My source is NY - LGA and destination is TX - DFW.

ASSISTANT: Do you have any price limit?

USER: The price should not exceed 5000.

ASSISTANT: Please wait a minute, I will check and get back to you.

USER: Sure.

ASSISTANT: Sorry, No flights found with your preferable dates.

USER: OK, no problem. Thank you for the information.

ASSISTANT: Thank you for opting us.