I finally have the answer to my bounty question from last year. I've posted the answer in my question but I cannot accept it. What should I do for this case?
Update your question, leave the contents the same but on the bottom add something like
EDIT: I found the answer see below posted by me
Or something to that effect.
Flag the answer for moderator attention and ask that they consider changing the accepted answer.
Alternately, post a new question with the correct answer, and ask on meta for help closing the old one as a duplicate of the new one.