You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Catherine Martinez.

ASSISTANT:  How can I help you?

USER: I would like to book a flight ticket from Dallas & Fort Worth TX-DFW, can you please assist me in booking a flight ticket to CO-DEN?

ASSISTANT: Ok, may I know your travel dates?

USER: My travel dates are 01/15 and 01/17.

ASSISTANT: Do you have any preference?

USER: I need a direct flight.

ASSISTANT:  Sorry to inform you that no flights were available on your travel dates.

USER: Ok, no worries at all. Thank you for your help.

ASSISTANT:  Thank you for availing us.