Complete your protest and mail it to the IRS address on the letter that explains your appeal rights. How to Write a Tax Protest Letter to the IRS Contesting an Issue.This form is to be used to request an Appeals review upon completion of an examination (audit) if you do not agree with our proposed changes from the audit. Petition for Reassessment. Complete all applicable blanks and type or print in ink. In order to file a small case request, simply follow the instructions listed on the letter explaining your rights to appeal and fill out Form 12203. We have provided sample letters that you can use to request waivers of several different types of IRS penalties. You may request a hearing with a member of the office of the Regional Director of Appeals when you file your appeal. Purpose of this form: You can use this form to appeal a Letter 4890 Notice of Denial or a Letter 5015 Notice of Revocation of your IRS-approved. You can find the CP or LTR number on the right corner of the letter.