You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I guide you at this moment?

USER: I am Barbara Evans, want to travel from OAK to DCA. Please help me in booking my ticket.

ASSISTANT: Sure, I am euphoric to help you with booking.

USER: Thank you.

ASSISTANT: May I know on which dates you are willing to travel?

USER: My travelling dates are from 02/20 to 02/22.

ASSISTANT: Do you like to go with a economy class or business class?

USER: I am looking for economy class.

ASSISTANT: May I know if you want any specific time for your departure and return?

USER: My depart time will be in the afternoon and my return time will be in morning.

ASSISTANT: Do you need any specifications in connection?

USER: I need a direct flight.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Thank you for waiting, sorry to inform you that unfortunately there is no flights available by the given details.

USER: It's ok, thank you.

ASSISTANT: Thanks for approaching us, have a nice day.