Resetting a Forgotten Administrator’s Password in Lion

Reader Lee Benjamin would like to reset his administrators password but it works the way it once did. In previous operating systems it was possible to insert the installation disc and strip the password entirely. Since Lion came from the App store, there is no installation disc to insert. Restart your MacBook Pro with the Option key held down and choose Recovery HD in the startup screen. If you like, you can enter a password hint in the appropriate field. When everything is configured to your satisfaction, click on Save.”]

Source: https://www.csoonline.com/article/2130551/resetting-a-forgotten-administrator-s-password-in-lion.html