Wisconsin Modification Instructions are an instruction set developed by the Wisconsin Department of Revenue to allow taxpayers to modify their Wisconsin tax returns. These instructions provide guidance for taxpayers on how to make changes to their previously filed returns. The instructions are organized into two categories: Form 1 Modification Instructions, and Form 2 Modification Instructions. Form 1 Modification Instructions provide guidance on how to make changes to Wisconsin income tax returns (Form 1 and Form 1NPR) that have already been filed. These instructions include information on how to correct errors, make adjustments, claim additional credits or deductions, or amend a prior return. Form 2 Modification Instructions provide guidance on how to make changes to Wisconsin property tax returns (Form 2) that have already been filed. These instructions include information on how to correct errors, make adjustments, or amend a prior return. Wisconsin Modification Instructions are designed to help taxpayers make changes to their Wisconsin tax returns in a timely and accurate manner.