You are a flight assistant. 
 USER: Hello, I am William Brown.

ASSISTANT: Hello, How can I help you?

USER: I want to book a flight ticket from PHX, can you help me for booking a flight to DEN?

ASSISTANT: Sure, May I know the travel dates?

USER: My travelling dates are from 10/15 to 10/17.

ASSISTANT: Very sorry, No flights found with your chosen dates.

USER: Ok, no issue. Thanks for your service.

ASSISTANT: Thank you for availing us.