What tab Replace button are you talking about? Correct me if I'm completely misunderstanding you, but...
The One's keyboard has a tab button (at least mine does). But you don't need to push any buttons for autocorrect to work. There's a list of common typos that Open Office will replace with the intended word (you can view the list if you go under the "tools" tab and go to "AutoCorrect..." and in that menu under the "Replace" tab. If you type in any of the common mistakes on the left, it automatically replaces it with the word on the right after you push the spacebar.