Depends just how bad it is.
You can hit it with sulphites, filter it and give it some time and re-evaluate.
I tried this once. Like an emotionally invested paramadec that couldn’t stop the cpr- while everyone else stood and watched. I Tried so hard.
Last step i added some finishing tannin to mask the flaws. And then I bottled. Thought it was acceptable at the time. But it wasn’t. It was terrible. And now it’s In the garage collecting dust awaiting disposal for years now.
here ix a method I have tried on some old wine kits. Calculate the amount of wine to be treated in liters, for each liter of wine measure out .5gram of powdered skim milk into 5 ml of cold water. stir into a solution. stir the wine vigorously and while swirling add the solution by pouring a single stream to make sure it enter below the wine surface. if poured on the surface it will have no affect. brown curds should develop. wait three days rack off of the curds and use a fining agent wait 10 days for fining action,sufphite and bottle. for old wine kits I add about a liter of a fruit concentrate to overcome any bad flavors.