I assume that the W-2c is for 2020, not 2021. You would only possibly be due an additional refund if you had more than one employer in 2020. If the Social Security tax (box 4) is the only change on the W-2c, it does not affect your 2020 tax return unless you had more than one employer in 2020.
If you had more than one employer in 2020, the W-2c does not affect your tax return unless the total amount of Social Security tax withheld from all jobs in 2020 is more than $8,537.40. Add up the amount in box 4 of all your W-2s, using the corrected amount on the W-2c. If the total is $8,537.40 or less, you are not due any additional refund. Do not file an amended return. If the total is more than $8,537.40, you had excess Social Security tax withheld, and the increase on the W-2c produced or increased the excess. You should file an amended return to get a refund of the added excess Social Security tax withheld.
If you are filing as married filing jointly, add up only the box 4 amounts for the person who got the W-2c. Do not include the other person's W-2s.
