You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Dennis Davis.

ASSISTANT: How can I help you today?

USER: I would like to book a ticket from DEN to DCA, can you please help me out?

ASSISTANT: Sure, can you share me your trip dates?

USER: I am travelling on these dates April 3rd and 5th.

ASSISTANT: Do you have any preferences?

USER: I prefer return time afternoon. I need a halt too.

ASSISTANT: Sorry to inform this, no flights are available on your travel dates.

USER: Ok no problem, thank you for your services.

ASSISTANT: Thank you for reaching us.