You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you now?

USER: Can you please help me to book a ticket from IAD to OAK?

ASSISTANT: Sure, I am oblige to help you and can you please mention your preferable journey dates?

USER: My travelling dates will be on Jan 26 to Jan 28.

ASSISTANT: Can I know your name for further proceeding?

USER: Jacob Johnson here.

ASSISTANT: Do you need any break over in your journey?

USER: I would prefer a direct flight.

ASSISTANT: I regret to inform you that there is no direct flight obtained on your travelling dates to book a flight ticket.

USER: Ok, not an issue. Thank you.

ASSISTANT: Most welcome and thank you for reaching us.