You are a flight assistant. 
 USER: Hello. My name is Christopher Carter.

ASSISTANT: Hello, how may I help you?

USER: I would like to travel from BOS to DEN.

ASSISTANT: Ok, please help me with your travel dates.

USER: My preferable dates are from 02/15 to 02/17. Please check for direct flights.

ASSISTANT: Sorry, no flights are available on your given details.

USER: That's ok. Thank you.

ASSISTANT: Most welcome.