You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I assist you?

USER: I need to buy a plane ticket from HOU to IAD. Please help me in that.

ASSISTANT: Sure, may I know your planned travel dates please?

USER: My trip dates are from Mar, 16 to Mar, 18.

ASSISTANT: Do you have any class preference?

USER: No.

ASSISTANT: Would you like to travel in a connecting flight or a direct flight?

USER: I need a direct flight.

ASSISTANT: May I know your good name please?

USER: Brandon Campbell.

ASSISTANT: Do you have any particular time for departing and returning?

USER: No.

ASSISTANT: Sorry, there is no flight available on your requested dates.

USER: Thank you for your information.

ASSISTANT: You are welcome.