You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you?

USER: I have planned to purchase a ticket to PHL from DFW, can you assist me in booking?

ASSISTANT: May I know your trip dates?

USER: I have planned my trip on 21st Mar and return 23rd Mar.

ASSISTANT: Please provide your connection limit.

USER: I need one connection between my trip.

ASSISTANT: Please let me know if you have any other specifications.

USER: My preference is always business class.

ASSISTANT: May I know your name?

USER: Joseph Allen.

ASSISTANT: Sorry, there is no flight running on your route.

USER: No problem, thank you for searching.

ASSISTANT: Thanks for choosing us.