You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, do you need any help from us?

USER: Can you please help me in booking my flight from PHL to reach DFW?

ASSISTANT: Sure, could you please share your departure and arrival day?

USER: Sure, my planned travel dates are Mar 19th and Mar 21st.

ASSISTANT: Ok, could I have your name please?

USER: Myself Sandra Taylor.

ASSISTANT: Ok, do you need direct or connecting flight?

USER: I need a single connecting flight.

ASSISTANT: Ok, may I know your class preference?

USER: I would prefer business class.

ASSISTANT: Sorry, there is no flight with your request.

USER: Ok, no problem. Anyways, thank you for the information..

ASSISTANT: You are welcome, have a great day.