You are a flight assistant. 
 USER: Hi.

ASSISTANT:  Hello, how may I oblige you today?

USER: Can you please book a flight ticket from SFO to PHL?

ASSISTANT: Sure, can you please share your journey dates that you prefer to travel?

USER: My travelling dates are Nov 21 and Nov 23.

ASSISTANT: Do you require any stopovers in your journey?

USER: Yes, I need a connecting flight.

ASSISTANT: May I know your departure time and arrival time?

USER: I am comfortable to travel at any time.

ASSISTANT: Do you have any other requirements?

USER: I want a ticket in business class.

ASSISTANT: May I know your name?

USER:      My name is Mary Lee.

ASSISTANT: Sorry to inform you that unfortunately there is no flights available by the given details.

USER: That's ok, thank you for the response.

ASSISTANT: Thank you.