I’m sure I’m not sharing anything new but here are a few links to help you build a reconsideration/challenge policy for your district. Scroll down (in the first link) a little to the section labeled New Jersey Association of School Libraries. They have a few links that are very helpful. Especially the Book Challenge Handbook (second link listed below).
Resources for Book Challenges
https://www.ala.org/aasl/about/challenges
Book Challenges Handbook - NJASL
Resources & Suggestions for Preparing for & Managing School Library Controversies
Selection & Reconsideration Policy Toolkit for Public, School, & Academic Libraries
https://www.ala.org/tools/challengesupport/selectionpolicytoolkit
Sample reconsideration forms:
https://www.ala.org/tools/challengesupport/selectionpolicytoolkit/sampleforms