You can make a published article draft anytime.

Within the editor, open the blog management panel on the left and find a post that you want to unpublish. Click on the ellipsis button ⋮ near the blog post title:

Click Unpublish, and your article will become a draft:

You can also unpublish it within the blog post editor: in the top toolbar, click on the Status:Public, and it will turn into a draft:

Finally, update your website for the changes to reflect online.

Learn more about managing blog settings 💡