You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: I have planned for the trip to Houston, can you please help me to reserve a plane ticket from DCA to IAH?

ASSISTANT: Sure, will you mention your travelling dates please?

USER: Thank you. My preferable travel dates are Apr 1st and Apr 3rd.

ASSISTANT: Do you have any preferences about flight connections?

USER: I need a direct flight to travel.

ASSISTANT: Do you have any preferences about flight timings?

USER: I am looking for a flight which is returning in the afternoon.

ASSISTANT: Please mention your name.

USER: Sure, I am Jack Wilson.

ASSISTANT: There is no flights found under your preferable details.

USER: It's ok, not a problem with that. Thank you for your time.

ASSISTANT: Welcome, have a great day.