We don’t currently have the ability to reset progress within Balance.
However, you can restart any Plan from the beginning. Each time you start a meditation you will be prompted to answer a set of questions, which will then tailor the Plan to your current needs. So if you’ve already answered those questions in the past, those answers will be overwritten by your latest responses. This will help ensure that the Plan is personalized to your current meditation needs and not to your past needs.