A reissued statement is one where someone asked the issuer for another copy. (It's possible that the originator of the W-2 insisted on corrections before it was filed with the IRS.) This is different from a corrected statement, which has different amounts listed for income, taxes withheld and non-taxable or tax-exempt income than the original W-2.
A corrected statement will have a box at the top with a checkmark that says "Corrected." It will be clearly labeled, so that you have no doubt whether it was corrected.