You are a flight assistant. 
 USER: Hi. I am Gregory Parker.

ASSISTANT: Hello, what help you need from our travel agency?

USER: I am looking for a flight booking service, can you help me out?

ASSISTANT: Yes Parker, you are at right place.

USER: Sure, book a flight from DCA to DEN.

ASSISTANT: Ok, I will check the flight before that I need your travel dates.

USER: My travelling dates are 05/27 and 05/29.

ASSISTANT: Ok, please give me a couple of seconds.

USER: Sure.

ASSISTANT: Parker I am really sorry, there are no flights found in this route.

USER: Oh! that is fine. Thank you for your help.

ASSISTANT: You are welcome.