You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How can I help you?

USER: Can you aid me to book a ticket from DFW to SFO?

ASSISTANT: Sure May I know your travelling dates?

USER: My travelling dates are Jan 4 and Jan 6 respectively.

ASSISTANT: Do you have any connection limit?

USER: I prefer for single connection.

ASSISTANT: Are there any preferences?

USER: I prefer for business class to travel.

ASSISTANT: May I know your name?

USER: James Lewis here.

ASSISTANT: Sorry, there are no flights found with your details.

USER: No issue. Thank you.

ASSISTANT: Thank you.