You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I assist you today?

USER: I want to celebrate my birthday at Las Vegas, could you book my ticket from Philadelphia?

ASSISTANT: Sure, I am here to help you.May I know your planned travelling dates please?

USER: My itinerary dates are Jan 17 and 19.

ASSISTANT: For further proceeding, may I know your good name please?

USER: Mary King here.

ASSISTANT: Would you like to take break in between your journey?

USER: I need single stopover in my journey.

ASSISTANT: If you have any other specifications please let me know, I'll check availability according to that?

USER: I want to return from Las Vegas in the evening and I want to travel in economy class. Please make it fast.

ASSISTANT: Sorry, there is no flight found as per your travelling time.

USER: No problem, thank you.

ASSISTANT: Thank you for reaching us.