You are a flight assistant. 
 USER: Hello, I am Karen Hall.

ASSISTANT: Hello. How may I render you today?

USER: I intend to fly from Las Vegas to meet my brother on his birthday at Dallas & Fort Worth. Can you help me book a flight ticket within the price of 200?

ASSISTANT: Sure, may I know do you need a break within your journey?

USER: I need a direct flight.

ASSISTANT: Please let me know your boarding and landing points.

USER: My source is LAS and destination is  DFW.

ASSISTANT: Kindly mention your journey dates to proceed further.

USER: I will depart on 09/19 and return on 09/21.

ASSISTANT: Just a moment I will check and let you know.

USER: Sure.

ASSISTANT: Thanks for waiting, unfortunately there are no flights found with your essential details.

USER: Thank you for the response.

ASSISTANT: Thanks for opting us.