This article will show you how to duplicate (i.e. create a copy of) an article that will not be affected by changes to the original article.
If you would like to have a copy of an article that has it's changes reflected in all copies of the article, you will want to reference the article (click here for more details).
Select Duplicate from the article action menu
Select the site, manual, and chapter where you would like to place the duplicate copy and click Duplicate Article.