You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you today?

USER: Please help me in booking flight ticket from OAK to DFW.

ASSISTANT: Sure, do you have any limits on number of connections?

USER: I need a direct flight.

ASSISTANT: Let me know your travelling dates.

USER: My trip dates are Oct 19 to Oct 21.

ASSISTANT: Please share your specifications.

USER: I don't have any more specifications.

ASSISTANT: Can I get your name?

USER: Myself Debra Green.

ASSISTANT: Sorry, there are no flights found based on your details.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for choosing us.