You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: Jason James here. I want to take part in Boston marathon, so please book my ticket from DTW to BOS.

ASSISTANT: Sure, May I know your travelling dates?

USER: My trip dates are Nov 17 and Nov 19.

ASSISTANT: Do you have any class preference?

USER: I prefer business class.

ASSISTANT: Do you have any other preferences?

USER: I want to depart in the afternoon.

ASSISTANT: Thanks for your details, there are no flights found on your data.

USER: No problem, thank you.

ASSISTANT: Thank you.