You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you?

USER: I am Debra Lewis. I need to book a flight ticket from DTW and OAK to meet my friends.

ASSISTANT: Sure, may I know your planned travel dates please?

USER: My travelling dates are 09/21 and 09/23.

ASSISTANT: Would you like to prefer direct flight or connecting flight?

USER: I need a connecting flight.

ASSISTANT: Do you have any particular time for departing and returning?

USER: I want to return in the morning.

ASSISTANT: Which class do you prefer?

USER: I comfortable with any class.

ASSISTANT: Sorry, there is no flight available in this route.

USER: No worries, thank you for the information.

ASSISTANT: Thank you for reaching us.