You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you for today?

USER: Can you please assist me in booking a flight ticket from IAD to DEN to attend a seasonal festival?

ASSISTANT: Yes, can you tell me your travelling dates?

USER: I am planning to start on May 18 and return on may 20.

ASSISTANT: Do you have any other specifications?

USER: I would like to depart in the afternoon time.

ASSISTANT: Do you have any preferences?

USER: I need a direct flight.

ASSISTANT: Give me a moment.

USER: Sure, take your time.

ASSISTANT: Sorry to inform you that there are no flights found on your requested dates.

USER: Ok, no problem.

ASSISTANT: Can I know your name?

USER: I am Jessica Allen. Thank you.

ASSISTANT: Thank you for contacting us.