It sounds like you initially received a W-2 with overtime, and then they corrected it to remove it? While that is unusual, if you have already filed and had your return accepted, I do not advise amending. Please first ensure you agree with the overtime you deducted. Keep in mind, only the "half" pay from time-and-a-half (the overtime premium) is deductible.
Save the W-2c for your records.
