If a letter is about a changed or corrected tax return, the taxpayer should review the information and compare it with the original return. You can find the CP or LTR number on the right corner of the letter.Complete your protest and mail it to the IRS address on the letter that explains your appeal rights. You generally have 30 days to respond to an IRS notice, so there's no reason to ignore it. Always check which tax year the notice relates to. If all required reports and payments are already on file, you may request a tax clearance letter using Webfile, or you may complete and return this request. Many find the easiest way to figure the entries for Form. X is to first make the changes in the margin of the return they are amending. We have provided sample letters that you can use to request waivers of several different types of IRS penalties. Review brief descriptions of IRS letters and notices taxpayers receive that include information about requesting an appeal.