The forms for this filing are available at the Property Appraiser's office, our website, or at the Department of Revenue's website. Complete the change of address form included with your tax bill and return it to the Property Appraiser's office.Form RP5217PDF is required whenever a deed is recorded with the county clerk's office. Form-RP-5217-PDF is required even if a property is not being sold. How to fill out the Nassau County Property Tax Grievance Form Instructions? 1. Read the eligibility criteria carefully. 2. Personal checks and credit card will NOT be accepted. For more information on Tax Deed Sales, call the Recording Department at 904-548-4604. Nassau County's deadline to file a property tax grievance is approximately 18 months in advance of the tax year being challenged, barring any extensions. How to fill out the Filing Instructions for AR20 in Nassau County NY?