That is one thing that bugs me about election night - the news outlets gush over the moment that someone gives a "concession" speech, as if that meant they were pulling their name off the ballot or something. No - the counting continues. And if, by some quirk, enough truly legitimate ballots were found to put that person over the top, then they would be certified as the winner, speech or no speech.
When you concede in chess (knock over your king), you are, in fact, declaring the other person the winner. When you "concede" an election, you're just publicly predicting that you'll end up with fewer votes once the counting is done - it does not affect the substantive procedure of counting all the votes and certifying the result.