Hi Oscar, 

I'm so glad to hear you're looking to use Khan Academy for your SAT and/or PSAT preparation!

To reset your practice test, please follow these steps:

1. Access the SAT practice section
2. Open the "Full Tests" tab
3. Select and scroll to the bottom of the test you'd like to reset
4. Click the "Reset this test" button

Note: You can only reset the entire test, not specific sections. Once you reset the scores for an exam, it cannot be undone.

I hope this helps! If you have any other questions, big or small, don't hesitate to let me know. :)

Best regards!