You navigate back to the Federal Wages&Income section, and edit whatever form-type you entered the withholding for. Editing it there corrects it.
Most commonly, the state withholding would be on a W-2, or 1099-R form....but can also be on a couple other form-types
____________*Answers are correct to the best of my knowledge when posted, but should not be considered to be legal or official tax advice.*