You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: I am Samuel Mitchell. I am planning to book a ticket from OAK to DFW. Can you please help me out?

ASSISTANT: Ok, please tell me your depart time of your journey?

USER: My depart time is evening.

ASSISTANT: May I know your travelling dates?

USER: I would like to travel on July 21 and return back on July 23.

ASSISTANT: Do you have any other requirements?

USER: Yes, I am looking for a connecting flight.

ASSISTANT: Ok, please wait.

USER: Sure.

ASSISTANT: sorry, no flights found on your route to reserve.

USER: That's fine, thank you for your service.

ASSISTANT: Thank you for taking assistance from us.