If your answer has been accepted, then the op has indicated that they found it useful. Whether or not it is correct is to an extent, besides the point, as such I don't see any reason why you would want to delete it. The community has already indicated that they feel another answer is better, through upvoting it. Removing your answer, isn't going to make that one the accepted answer.
If it's to prevent future downvotes, then an obvious option would be to edit your answer and indicate that one of the subsequent answers has offered extra information that has changed your mind. In most cases, that would be enough. You could also comment to the OP that asked the question, suggesting that they change their accepted answer (although in this case it seems unlikely to work, since they seem to have gone away).
What I find odd about your request is that you've also provided this answer on a different question, which hasn't been accepted, has a similar number of downvotes and could have been deleted, but hasn't been.