You have to return to the exact same field where you entered the amount and clear the field. To do that, when you go toLess Common Income/Gambling Winnings, selecting No will not do anything. You have to continue to the exact same field where you entered it originally and delete it. So, on the "did you win money...." select Yes and that will let you continue to either a W-2G area or the area not reported on a W2G and get to the field where you made the original entry.
