You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

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

ASSISTANT: Sure, we are here to help you. Can you share me your travelling dates?

USER: My itinerary dates are Sept 25 and 27.

ASSISTANT: May I know your name?

USER: Carol Phillips here.

ASSISTANT: Let me know your airport codes?

USER: My genesis and terminus airport codes are PHL and LAS.

ASSISTANT: Do you have any other specifications?

USER: I need a direct flight.

ASSISTANT: Ok, wait for some time.

USER: Sure.

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

USER: No problem, thank you.

ASSISTANT: Thanks for approaching us.