Windows allows you to change the product key it's activated with. This lets you upgrade to a different edition of Windows 10, or switch to another key if you're reusing licenses or a key has been revoked.
There's multiple ways to change product key, including terminal solutions you can run from the command prompt. For this guide, we'll show you the simplest way using the Windows 10 Settings app.
Open Settings from the Start menu or the Win+I keyboard shortcut. Click the "Update & security" category and then the "Activation" page from the left menu. On the screen which appears, click the "Change product key" link.
A popup prompt will appear. Type in your new product key to begin the activation process. Your key will be 25 characters long and will be included in your Windows purchase confirmation email, or within physical installation media. If you’re using a retail device, such as a laptop or desktop PC, you may also have a product key sticker affixed to your machine.
Click "Next" and follow the prompts to approve the product key change. Windows will now attempt to activate your key. Generally, this will be an automated online process. As long as your key is genuine and unused, you should be activated within a few minutes. Your product key will now be installed, and all the features of your Windows 10 edition should be unlocked by the key.