You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you?

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

ASSISTANT: Please provide your journey dates.

USER: My travel dates are 19 to 21 of Jan.

ASSISTANT: Do you need any connection limit?

USER: I need a connecting flight.

ASSISTANT: Are there any other specifications?

USER: I prefer to travel in business class.

ASSISTANT: May I know your name?

USER: I am Joseph Brown.

ASSISTANT: There are no flights available on your routes.

USER: Oh! that very sad to hear, thank you.

ASSISTANT: Thank you for choosing us.