You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Sarah Harris here.

ASSISTANT: How can I help you?

USER: Can you please book a ticket from DTW to IAD? As I'm planning to visit Washington.

ASSISTANT: Sure, I will help you. May I know your depart and arrival dates?

USER: Yes, my planned departure and return travel dates are 19th and 21st of June.

ASSISTANT: Do you prefer a lay by in between your journey?

USER: Yes, I need 1 halt in between my journey.

ASSISTANT: In which class, would you like me to book your flight ticket?

USER: Any of the classes is ok for me.

ASSISTANT: Give me a minute, I will let you know the flight availability.

USER: Sure.

ASSISTANT: Thank you for your time, there were no flights available that matches your requirements.

USER: Oh! That's ok, thank you for giving the infromation.

ASSISTANT: Thank you for approaching us.