The answer to 'how to unclog plumbing repair' is to use a plunger or a drain snake to clear the clog. First, try using a plunger to dislodge the blockage. Firmly place the plunger over the drain opening and plunge up and down vigorously for 15-20 seconds. If the plunger doesn't work, use a drain snake (also called a plumber's snake or auger) to physically break up the clog and pull it out.
If the clog persists or you're unable to clear it, it's best to call a professional plumber. They have specialized tools and expertise to safely and effectively clear even the toughest clogs without causing further damage to your plumbing system.