You go back to the answer and click the edit button at the bottom of your answer. You have to be logged in and it has to be your answer you edit. If you have a profile, all of the questions you have answered are available in your profile. Also when you go to this answer forum, on the top of the page one of the options is “My Feed”. Click that and one of your choices is ‘Questions Answered”. You should be able to edit from there.
Like I just did to add this bit to this answer.