You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Stephen Campbell here.

ASSISTANT: May I know your concerns regarding the flight?

USER: Can you please help me in booking a flight ticket from DCA to DEN?

ASSISTANT: Yes, I will assist you with that. May I know your travel dates to book?

USER: Sure, my travel dates are from 04/15 to 04/17.

ASSISTANT: Ok, please wait a moment.

USER: Sure, I will wait for your response.

ASSISTANT: Thank you for waiting, there are no flights available at the location you willing to depart. Sorry for the inconveniences.

USER: Ok, no problem, I will check out with another agency. Thank you for the information.

ASSISTANT: Thank you for connecting with our agency.