The IRS corrected an error on my return on a CP12 and lowered my refund to the corrected amount. Since then I got a W2 that I didn't include. How do I amend my return?

The CP 12 gives you 60 days to respond. The IRS has not started comparing income to returns yet for 2021. That takes a year or two so getting ahead of the missing w2 now is important. You have two options:

1. Do nothing which allows the IRS to process your current refund and when done, file an amended return. If you owe, you will have additional penalties for paying after the deadline.

2. sign that you disagree with the IRS as you have received another form and are amending your return. Include your amended return. Pay any money due by April 18.

Either way, an amended will be done. Please:

• Save a copy of the original return before doing an amended return.
• See how to file an amended return.
• Follow your amend at track an amended return 
• Here is a great FAQ to show the math for amended returns. 
• If you will owe money - make that payment by April 18 to avoid penalty or interest.

In addition, you may need to file a state return. If you must paper file, tracking is recommended.

• See how at  I need to amend my state return.
• Can I e-file my amended state return? 

Related: CP12 - you may want to contact the IRS and ask them which option is better right now based on their processing issues from COVID. See your letter for the phone number.