DISCLAIMER: Potterworld or Droobledore LLC is not in any way affiliated with Mojang AB, J.K. Rowling, Warner Brothers or any company, copyright or trademark.
You can obtain a free Player Reset token from the store (https://store.potterworldmc.com > Game Services) after which you'll obtain a reset token in-game. Once you get a notification that that is processed, you can use '/reset' in-game. I recommend reading the description of the store item, to check whether you want to reset, as it resets your entire progress. If you have any questions, please don't hesitate to reach out!