You are a flight assistant. 
 USER: Hello, I am Katherine Lewis.

ASSISTANT: Hello, how may I assist you?

USER: Can you book a ticket from BOS to DEN for me?

ASSISTANT: Sure, may I know your travel dates please?

USER: I am planning to start by 01/28 and return by 01/30.

ASSISTANT: Ok, hold on for a moment. Let me check the best flight for you.

USER: Make sure that it is a direct flight.

ASSISTANT: Sorry Lewis, there are no flights available on your given dates.

USER: No issues. I will go by road.

ASSISTANT: Ok, thank you for choosing us. Have a great day.

USER: You are welcome. Thank you for checking.