You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you?

USER: Could you book my ticket in business class?

ASSISTANT: Sure, may I know your preferred dates?

USER: My itinerary dates are Dec 25 and 27.

ASSISTANT: May I know your airport codes?

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

ASSISTANT: Do you need any other requirements?

USER: I need a connecting flight.

ASSISTANT: May I know your name?

USER: Elizabeth Miller here.

ASSISTANT: I regret to inform you that there are no flights obtained on your journey dates to book a flight ticket.

USER: No problem, thank you.

ASSISTANT: Thank you for opting us.