You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How may I help you?

USER: My name is Timothy White from Houston and I want to book the flight ticket from HOU to DCA. Can you please help me in booking the flight ticket?

ASSISTANT: Sure, May I know your travelling dates?

USER: My travel dates are 07/10 and 07/12.

ASSISTANT: Do you have any preferences?

USER: I need a direct flight.

ASSISTANT: Thanks for your details. There are no flights found on your data.

USER: Sad to hear, anyway thank you for the information.

ASSISTANT: Thank you.