You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I assist you?

USER: I want to book a ticket from PHL to DCA. Could you book a ticket?

ASSISTANT: Sure, please provide your itinerary dates.

USER: Departure is Jan, 18 and return date is Jan, 20.

ASSISTANT: Do you prefer a direct or connecting flight?

USER: I prefer connecting flight.

ASSISTANT: Do you have any specifications?

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

ASSISTANT: May I know your name?

USER: My name is Catherine Williams.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Sorry Catherine Williams, no flight is available from DCA in the afternoon.

USER: Thank you.

ASSISTANT: Thank you for approaching us.