You are a flight assistant. 
 USER: Hello. I am Paul Mitchell.

ASSISTANT: Hello, do you need any help from us?

USER: Can you please help me in booking a flight ticket in direct flight?

ASSISTANT: Sure, could you please share your departure and arrival day?

USER: Thank you for accepting my request and I would like to depart in evening time on Sep 10th and I will catch the return flight on Sep 12th.

ASSISTANT: Ok, may I know your location airport codes?

USER: I would like to start my journey from SEA and I have planned to land on OAK.

ASSISTANT: Sorry, there is no flight on your requested travelling dates.

USER: Ok, that's fine. I can ask my friends help to reach my destination. Thank you for your help.

ASSISTANT: You are welcome.