You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I serve you?

USER: I want to book a flight ticket from IAD to LAS. Could you help me in booking?

ASSISTANT: Sure, I will help you. Please send your travelling dates.

USER: My travelling dates are from Jan 14 - 16.

ASSISTANT: Do you have any preferences?

USER: I prefer for connecting flight.

ASSISTANT: May I know your name please?

USER: Kimberly Williams.

ASSISTANT: Sorry, there is no flight available with your requirements.