Did you already file? If so, you will need to amend your return. If you have not filed, you can go back into your return and enter the W-2c information.
Please see this Turbotax FAQ for more information, https://ttlc.intuit.com/community/entering-importing/help/i-got-a-w-2c-from-my-employer-how-do-i-handle-this/00/26330