You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you today?

USER: I am looking to book a flight ticket from IAD to SFO. Can you help me for that?

ASSISTANT: Sure, I am here to help you. May I know your travel dates please?

USER: My travelling dates are Oct 07 and Oct 09.

ASSISTANT: Ok, do you have any specifications?

USER: I prefer to book a single connecting flight.

ASSISTANT: Ok, may I know your name please?

USER: My name is Larry Evans.

ASSISTANT: Sorry Larry Evans, there are no flights available on your requested dates.

USER: That's ok, thank you for checking.

ASSISTANT: Welcome, thank you for choosing us. Have a great day.