What this notice is about We made a change to your return that affects how we apply the estimated tax payment. What you need to do Follow the instructions in your notice carefully. Correct the tax return copy you keep for your records to avoid a possible underpayment of next year's taxes. Frequently asked questions How do I change my estimated tax payments? Use Form 1040-ES, Estimated Tax for Individuals PDF. For more information, see Publication 505, Tax Withholding and Estimated Tax PDF. How can I find out what caused my tax return to change? If you need more information that you see on the notice, you can contact us at the number listed on your notice. What should I do if I disagree with the changes you made? Contact us at the toll-free number listed on the top right-hand corner of your notice, or by mail using the contact information section of the notice. Tips for next year Consider filing your taxes electronically. Filing online can help you avoid mistakes and find credits and deductions that you may qualify for. In many cases you can file for free. Learn more about e-file. Reference Tools Publication 1, Your Rights as a Taxpayer Full list of tax forms and instructions Need Help? You can authorize someone to contact the IRS on your behalf. If you can’t find what you need online, call the IRS number at the top of your notice or letter.