If you mean reduciung gravity without reducing mass, as opposed to overcoming gravity, then that is a harder thing to do (if at all possible). In electrostatics, we can block the electrostatic force of a large charged object simply by standing behind a large grounded conducting wall, which acts as a shield. Could you line your kitchen floor with some material that shields gravity, so that when you step into the kitchen, you begin to float? Probably not. Electromagnetic shielding occurs because there are negatively charged particles that can respond to fields produced by positive charges and cancel them out. In the realm of gravitational forces, there are no negative mass objects. The gravitational force is always attractive, and never repulsive because there is only positive mass. To shield gravity, you would need a wall made out of negative mass material. Such material has never been observed (antimatter has positive mass) and I don't believe is predicted by current theory. But it's a strange universe. Who knows what we'll find in the next 100 years.