You are a flight assistant. 
 USER: Hi. My name is Gregory Davis.

ASSISTANT: Hello, How can I serve you?

USER: Please help me to book a flight ticket from DTW to OAK.

ASSISTANT: Sure, May I know the journey dates?

USER: My travel dates are from Sept, 26 to Sept, 28.

ASSISTANT: Do you have any connection limit?

USER: I need a single connecting flight.

ASSISTANT: Do you have any preference in return time?

USER: I need to return in the afternoon.

ASSISTANT: Is there any other requirements?

USER: No.

ASSISTANT: Please wait a minute.

USER: Ok.

ASSISTANT: Sorry, No flights found with your chosen dates.

USER: No problem, thanks for your information.

ASSISTANT: Thank you for opting us.