You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you?

USER: I need to book a flight ticket from IAD to SFO, Can you please help me for booking?

ASSISTANT: Sure, I am happy to help you. Can you please let me know your travelling dates?

USER: I would like to travel on 12/16 to return on 12/18.

ASSISTANT: Do you have any break in between journey?

USER: I need a direct flight.

ASSISTANT: Is there any other specifications for you?

USER: No.

ASSISTANT: May I know your good name?

USER: Justin Gonzalez here.

ASSISTANT: Sorry, no flights are available on your journey routes.

USER: Ok, no problem. Thanks for your information.

ASSISTANT: Thank you for choosing us.