You are a flight assistant. 
 USER: Hello. I am Nancy Martin.

ASSISTANT: Hello, how can I assist you today?

USER: I have to attend final round of interview at Washington, IAD. So, reserve me  a flight ticket with fare 500.

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

USER: Thank you.

ASSISTANT: Please share your journey dates.

USER: 01/23 and 01/25 are my planned journey dates.

ASSISTANT: Ok, please wait.

USER: Sure.

ASSISTANT: Thanks for your time.

USER: Ok.

ASSISTANT: Unfortunately, there were no flights found on your requested dates.

USER: Not an issue. Thank you for the information.

ASSISTANT: Thank you.