You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: I am Deborah Nelson. Can you please help me to book a flight ticket from OAK to DTW?

ASSISTANT: Sure, I am happy to help you with the ticket booking.  Could you please help me with your travel dates?

USER: Sure, my travelling dates are on 01/29 and 01/31.

ASSISTANT: Ok, do you have any airlines preference?

USER: Yes, I need a business class.

ASSISTANT: Ok, do you have any other specifications?

USER: My return time should be morning.

ASSISTANT: Ok, please give me a minute. I will search the flight and get back to you.

USER: Sure.

ASSISTANT: Sorry to tell you that, I have not found any flight availability in this route on the dates you have given.

USER: Ok, not an issue. Thank you.

ASSISTANT: You are most welcome. Thank you for reaching us.