The IRS uses Letter 474C to inform you of changes to your return, usually regarding some credit. Often, it means you owe less tax or will receive a bigger refund. Read the notice carefully ... what it is about and what you can/need to do is clearly posted. Are they referencing the original return or the amended return you sent? Amended returns take 20+ weeks to process so chances are the notice is on the original return and the IRS made some changes for you.
If you agree with their changes then send the agreement voucher with the payment.
