You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you today?

USER: I am Donald Hernandez. I want to reserve my flight ticket from Washington, DCA to Chicago, ORD.

ASSISTANT: I am happy to help you with that.

USER: Thank you.

ASSISTANT: Can you please provide your travelling dates?

USER: Travelling dates are on 06/15 and 06/17.

ASSISTANT: Wait for a moment.

USER: Sure.

ASSISTANT: I am sorry to say that there is no flight found.

USER: Ok, thank you.

ASSISTANT: Thank you for reaching us.