You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you today?

USER: I want to book a flight ticket to DCA and celebrate my sister birthday, can you help me with booking a connecting flight?

ASSISTANT: Sure, I will help you with book.

USER: Thank you.

ASSISTANT: Please mention your source airport code?

USER: My source airport code is ATL.

ASSISTANT: May I know on which dates would you like to travel?

USER: I will fly on Nov 15 and recur on Nov 17.

ASSISTANT: Please mention your depart and return flight timing?

USER: My return time is morning.

ASSISTANT: Do you have any other preference?

USER: I would like to prefer normal-cost airline.

ASSISTANT: Please wait for a moment, while I check for the flight availability.

USER: Sure.

ASSISTANT: Thank you for waiting, sorry there is no flight available on your given journey dates.

USER: Ok, no problem.

ASSISTANT: May I know your name for records?

USER: I am Lisa Hernandez.

ASSISTANT: Ok, thank you for your name.

USER: Thank you for your information.

ASSISTANT: Have a nice day ahead.