You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you today?

USER: I am Jacob Davis. I need your help in booking a ticket to DCA from DEN.

ASSISTANT: Sure, may I know your dates of travelling to proceed?

USER: My travelling dates are from 06/18 to 06/20.

ASSISTANT: Ok, please wait a moment, let me search a flight for you.

USER: Ok.

ASSISTANT: Thanks for waiting, sorry, unfortunately no flights found on that day.

USER: Ok, Thanks for your information.

ASSISTANT: You are welcome, have a nice day.