A reprimand is something like a notification about a certain situation you were involved into. On an ethics and compliance solutions study, you have to at least explain yourself in a polite way what caused you to do such situation or tell you part about it.
Use your voice, and tell it what you didn't want it to do. Make sure you do this right after the dog did it and in the place where it happened, so the dog understands. It is never okay to hit a dog....