"Letters of Office" is not really a letter. Every person entitled to request a correction, must complete an Affidavit and Certificate of Correction Request (see FORMS in the right-hand column).Use our Affidavit of Death form to verify the death of a family member and help with the inheritance process. This comprehensive guide aims to help you unravel the complexities of using a Small Estate Affidavit in Illinois. Have you lost a loved one in Illinois? This in-depth article provides a detailed checklist of the Top 15 things to do after someone dies in Illinois. You'll need the person's Social Security number and certified copies of their death certificate for most agencies and programs. Social Security and Medicare. Important documents such as a Will and "Final Instructions" letter might be in the safe box. Parents who, for the month of death, were entitled to a monthly benefit on the same record as the deceased;; A surviving spouse not qualified under 1.