If you look at the Form W-2 published by the IRS you will see this on the top of Copy A and Copy D. Copy A is submitted to the Social Security Administration and Copy D is retained by you, the employer. According to the IRS instructions for Forms W-2:

“If you discover an error on Form W-2 after you issue it to your employee but before you send it to the SSA, check the “Void” box at the top of the incorrect Form W-2 on Copy A. Prepare a new Form W-2 with the correct information, and send Copy A to the SSA. Write “CORRECTED” on the employee’snew copies (B, C, and 2), and furnish them to the employee. If the “Void” Form W-2 is on a page with a correct Form W-2, send the entire page to the SSA. The “Void” form will not be processed. Do not write “CORRECTED” on Copy A of Form W-2.”