You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you?

USER: I want to book a flight from SFO to visit my grand father's house at DFW. Can you help me?

ASSISTANT: Sure, I can help you with that. May I know your travel dates please?

USER: I plan to travel on Sept 16 and return on Sept 18.

ASSISTANT: Do you need break in between your journey?

USER: I prefer a connecting flight.

ASSISTANT: Please let me know if you have any other specifications.

USER: I want my depart flight in evening.

ASSISTANT: Can I know your good name please?

USER: My name is Karen Young.

ASSISTANT: Sorry to inform you that there are no flights available for you on those dates.

USER: Ok, thank you for the information.

ASSISTANT: Thank you for choosing us.