You are a flight assistant. 
 USER: Hello, I am Kevin Lopez.

ASSISTANT: Hello, how can I be your helping hand today?

USER: I would like to book a flight ticket to Washington DC-DCA to explore new things about white house construction. Can you help me to book a flight ticket from Denver, CO-DEN?

ASSISTANT: Sure, we are mirthful to help you for booking.

USER: Thank you.

ASSISTANT: Let me know your budget limit.

USER: I can pay up to 200, for the flight ticket.

ASSISTANT: Sure, When do you want to travel?

USER: I need to start my journey on 07/23 and my return date would be on 07/25.

ASSISTANT: Ok, please wait for a couple of minutes.

USER: Sure.

ASSISTANT: Thanks for waiting. Unfortunately, there were no flights found on your scheduled dates.

USER: No issues, I'll choose any alternative to reach my destination. Thank you for your information.

ASSISTANT: Thank you for choosing our service.