You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you today?

USER: Can you please help in booking the flight ticket from DEN to OAK?

ASSISTANT: Sure, may I know your travel dates?

USER: My departure date is July 5th and my return date is 7th.

ASSISTANT: Do you have any preferences?

USER: I need a direct flight.

ASSISTANT: Can you mention your name to proceed further?

USER: Samuel King.

ASSISTANT: Sorry, no flights found as per your requirement.

USER: Ok, thank you for the service.

ASSISTANT: Thank you for reaching us.