The WordPress publish date (or timestamp) is a handy tool to help you sort your content.
Here’s how to quickly change the date of a post.
The easiest way to change the sort order of your posts is to change the date. Later (or more recent) posts usually show up first unless you’ve forced it otherwise.
To change that, the quickest way is through the Quick Edit dialog when you hover over a post in Posts –> All Posts. Choose Quick Edit and just manually change the date to later or earlier than the post you want it to be higher or lower than in your sort order. Update the post and you’re done. Need to do more posts, just change each one.
Another trick is that you can always change the date again if you no longer care to have your sort order the way you wanted it. Last tip is that you can also “hide” posts (kinda) by making the publish date farther in the past. Later, if you’d like, you can change it back to the date it was originally published if that helps for your organization of content. For example, I like to have my portfolio items relatively accurate as it reminds me when we finished that project with a client.