Yes, depending on the information. An employer will sometimes issue a completely separate W-2 for a different state and they sometime put it on the second line of the W-2. You can add another row and treat lines 15-20 as if they put it on the second line of the W-2. This should be the only change you make. You want to be careful not to duplicate other information. If you feel there was an error elsewhere on the forms, you may call your employer.
