You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, Good Morning.

USER: My name is Karen Thomas.

ASSISTANT: How may I guide you?

USER: I would like to visit DFW to attend a business meeting, so I want a direct flight from LAX.

ASSISTANT: Sure, can I know your preferable dates you are intrested to travel?

USER: I want to travel from 03/18 to 03/20.

ASSISTANT: Please hold on for a moment, let me check for any available flights.

USER: Ok, please check.

ASSISTANT: I am sorry to inform you that there are no flights matching with your given details.

USER: That's fine. Thank you for your valuable time.

ASSISTANT: Thank you, have a good day.