You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you today?

USER: Please book a ticket from SEA to SFO to attend Innovation festival to share my ideas.

ASSISTANT:  Sure, can you please mention your departure and arrival dates of your journey?

USER: My travelling dates are Dec 1 and Dec 3.

ASSISTANT: Thank you, may I know your name please?

USER: Sure, I am Barbara Williams.

ASSISTANT: Sure, is there any another specifications on your trip, so that I can book a ticket as per your wish?

USER: Yes, I want a direct flight.

ASSISTANT: Sorry, there is no flight found with your requirement.

USER: Ok, Thank you for your help.

ASSISTANT: Welcome, thank you for reaching us.