Even theoretically, we have no prospects for manipulating gravity. No way to, say, generate a gravitational force without a lot of mass or remove the gravitational influence of a large mass. The closest we can get is tricks like using freefall-like motion to simulate microgravity within Earth’s gravitational field. Or (and I don’t think this one’s been done, but it’s theoretically pretty straightforward, if involved engineering-wise) using rotation to mimic the effects of gravity in microgravity. I suppose one could also argue that being in orbit simulates microgravity even though you’re well within the gravitational influence of Earth. Oh, I guess I can also mention that people training to be astronauts sometimes train underwater because that simulates some of the conditions of microgravity. But yeah. The closest we come to what you’re asking about is “tricks”.