You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. Is there any help that you need from our agency?

USER: I am Frank King from Oakland. Could you please help me in flight ticket booking process from OAK to DCA?

ASSISTANT: Sure, we can help you and on what dates that you are willing to book your flight ticket?

USER: Thank you for your response, I want to take off on Aug 26 and please confirm my return ticket also on Aug 28.

ASSISTANT: Do you need business class or economy class?

USER: I want to travel in business class flight so please check with this.

ASSISTANT: Please be on hold for a moment to check for a flight.

USER: Ok.

ASSISTANT: Sorry, there is no flight obtained on your journey dates.

USER: Oh! It's ok no problem.

ASSISTANT: You are most welcome and have a nice day.

USER: Thank you for your information.