Consider the case of an answer that you have provided that receives half a dozen upvotes and is accepted by the original poster. However later you discover that your answer is incorrect. Nobody else has submitted a correct answer but you are now in a position to do so.
What is the approved procedure in this case? Should you edit the answer, retaining reputational points for your previous incorrect answer, or delete the answer and provide a completely new one for list members to reassess?