You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Elizabeth Campbell.

ASSISTANT: How may I help you today?

USER: Can you help me to book a flight from DFW to BOS?

ASSISTANT: Sure, let me know your travel dates please?

USER: My travel dates are Dec 15 and 17.

ASSISTANT: Ok, is there any class preference?

USER: I need a business class.

ASSISTANT: Do you have any specific depart and arrival timings?

USER: I want to return in the morning time.

ASSISTANT: May I know your connection limit?

USER: I need a break.

ASSISTANT: Do you have any other specifications?

USER: No.

ASSISTANT: Sorry to inform you that there are no flight services available on your given dates.

USER: Ok, thank you.

ASSISTANT: Thanks for opting us.