You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Paul King here.

ASSISTANT: How may I assist you at this moment?

USER: Can you please help me in booking a flight ticket from IAH to DCA?

ASSISTANT: Sure, I will help you with that. Can you please provide your preferable dates of travelling?

USER: Sure, my travel dates are from Aug 27 to Aug 29.

ASSISTANT: Do you have any class preference?

USER: No, I am comfortable with any class.

ASSISTANT: Do you have any particular timings in departure and arrival?

USER: Yes, I need to depart in the afternoon.

ASSISTANT: Do you have any connection limit?

USER: I am looking for a direct flight.

ASSISTANT: Please hold on a moment to check the flights.

USER: Sure, I will wait for your response.

ASSISTANT: We regret to inform you that, there are no flights available with your required specifications.

USER: Ok, no issues. Thank you for the information.

ASSISTANT: Thank you for approaching us, have a great day.