What precepts do you mean? Lay precepts are for life, bodhisattva precepts are until buddhahood, monastic precepts are for life. What you can give back are the monastic (Vinaya) precepts, but to be re-ordained it takes the community to approve it. Otherwise you don't lose the other vows. You can do repentance on your own of course, and remind yourself of the vows you took.
"To know by thinking falls into the secondary. To know without thinking falls into the tertiary."(Yangshan Huiji, X1405p58b18-19; tr. JC Cleary: A Tune Beyond the Clouds, p 43)"While teachers of the middle way, mind only, transcendent wisdom, mantra, and other schools may have their own assertions, the fulfillment of those intentions is the same. There is not a single thing that is not contained within mind."(Gampopa to Düsum Khyenpa, in "The First Karmapa", KTD Pub, p 254)Mahayana LinksThe European Buddhist Blog