Due process is a legal procedure you can take when you feel your rights are violated. However, it's not that simple.
I refer to books:
-The Complete IEP Guide: How to Advocate for Your Special Ed Child by Attorney Lawrence M Siegel
-The Complete Special Education Guide to Special Education by Linda Wilmshurst, Ph.D. & Alan W. Brue, Ph.D.
-2020 Lawyer's Reference Guide: Individuals with Disabilities Act (IDEA) Regulations as of February 14, 2020 by U.S. Department of Education