You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Paul Lee.

ASSISTANT: How may I help you?

USER: Can you please help me in booking a flight ticket from IAD to ATL?

ASSISTANT: Sure, may I know your trip dates?

USER: I would like to fly on Mar 27 to Mar 29.

ASSISTANT: Do you have any class preferences?

USER: I am comfortable with any class.

ASSISTANT: May I know your connection limit?

USER: I need a single connection.

ASSISTANT: Can you please share your airline preferences?

USER: I am comfortable with any airline.

ASSISTANT: Do you have any specifications?

USER: I would like to depart in evening time.

ASSISTANT: Sorry, there are no flights found on your trip dates.

USER: Not an issue. Thank you.

ASSISTANT: Thank you for reaching us.