The two most difficult terms for many parents to navigate are IEP and 504. The degree of protection and services can vary greatly, between the two "labels." 

From the website, www.understood.org/en/school-learning/special-services/504-plan/the-difference-between-ieps-and-504-plans--

"Both Individualized Education Programs (IEPs) and 504 plans can offer formal help for K–12 students with learning and attention issues. They’re similar in some ways but quite different in others. 
Knowing which laws do what is a big part of understanding the difference between an IEP and a 504 plan. Explore more details about your child’s legal rights. And if you need help navigating special education law in your state, consider reaching out to your local Parent Training and Information Center. The people there can answer questions and give practical advice on issues specific to your area.
This chart compares them side-by-side to help you understand the differences."
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