Yes you change the article content for your project. All you need to do is to click on the "Edit Project" button from your existing articles tab and your existing project will be reopened for editing.

You can click on this change button to change the content of your article. Please note that changing the content of your article will recreate the whole project. 

So, if you want to make only minor changes in your article please use the Text editing option of that individual text in Step 3 instead.