You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: I am planning to book a ticket from BOS to ORD. Can you please help  me out?

ASSISTANT: Yes, can you tell me your dates of travel?

USER: I am planning to travel on June 12 and return back on June 14.

ASSISTANT: Do you have any preferences?

USER: My return time should be afternoon.

ASSISTANT: Give me a moment.

USER: Sure.

ASSISTANT: Sorry to inform you that there are no flights found on your requested dates.

USER: That's fine, thank you for your service.

ASSISTANT: Thank you for reaching us.