You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I be at your service today?

USER: I am looking for a flight from HOU to DEN, can you help me?

ASSISTANT: Sure, I will help you in booking the ticket. May I know your travelling dates please?

USER: My travel dates are 27 to 29 of Mar.

ASSISTANT: Do you have any other specifications?

USER: I need a direct flight.

ASSISTANT: Please help me with your name for booking.

USER: Patricia Johnson here.

ASSISTANT: Sorry for this inconvenience, I could not find any flight with your requirements.

USER: Oh! that very sad to hear, thank you.

ASSISTANT: Thank you for reaching us.