You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: I am Kathleen Smith. I have to attend a Live Concert at San Francisco, could you please help me with booking a flight ticket from DTW to SFO?

ASSISTANT: Sure, can you please share your travel dates?

USER: I would like to depart on Dec 29th and return on Dec 31st.

ASSISTANT: Do you have any class preference?

USER: I am comfortable with any class.

ASSISTANT: May I know your connection limit?

USER: I need a connecting flight.

ASSISTANT: Do you have any other specification that you are looking for?

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

ASSISTANT: Kathleen Smith, I am sorry to inform you that there is no flight available at your request.

USER: Ok, not an issue. Anyways, thank you for the information.

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