You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I address you?

USER: I want to book a ticket from OAK to DTW, can you assist me in booking my ticket?

ASSISTANT: Sure, on what dates are you planning to make your trip?

USER: My preferred dates are Sep 11th and Sep 13th.

ASSISTANT: Do you need a connecting flight or direct flight?

USER: I need single connection between my trip.

ASSISTANT: Any other requirements to be met?

USER: Make sure that my depart time must be evening.

ASSISTANT: Please forward your name.

USER: Elizabeth Hill.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Thank you for waiting, I regret to inform you that there are no flights obtained on your journey dates to book a flight ticket.

USER: No problem, thank you for searching.

ASSISTANT: Thank you for opting us.