Penny is right! I am a school psychologist and I know Section 504 like the back of my hand. I have read every word of Section 504 (multiple times) so that I can do the best for my students when helping develop their 504 plan.
Section 504 protects all students against discrimination based on disability status. This means that a 504 plan is developed so that a student may receive FAPE (free appropriate public education). FAPE in regards to specialized education under Section 504 is education that meets the needs of the student as adequately as the needs of a non-disabled student (34 CFR § 104.33b). What also could be referenced is 34 CFR § 104.22 regarding accessibility; it states that a 504 plan will “[give] priority to those methods that serve handicapped persons in the most integrated setting appropriate.” In regards to academia, Section 504 says this: “[a public school] shall provide for the education of each qualified handicapped person in its jurisdiction with persons who are not handicapped to the maximum extent appropriate to the needs of the handicapped person.” (34 CFR § 104.34a) May times Section 504 mentions placement in a “regular educational environment,: but nowhere in Section 504 does it explicitly bar providing service to those in honors or accelerated classes.
A similar concept that your school may be able to understand better is what they are doing by not providing your daughter to retake her test can be assimilated to not providing a braille textbook to a child who is blind, simply because that textbook is “honors.”
While it is true that Section 504 does not provide students with significant alteration to curriculum content (that’s what an IEP does), increased time or retaking exams is a common allowance schools may make to provide FAPE to students with disabilities.
Bottom line: your child has a 504 plan, the school is required by federal law to provide the accommodations outlined within that document in all school settings (even after school extracurriculars).
Here is a helpful guide to understanding Section 504: https://www2.ed.gov/about/offices/list/ocr/docs/504-resource-guide-201612.pdf
And here is a link to read Section 504 for yourself: https://www2.ed.gov/policy/rights/reg/ocr/edlite-34cfr104.html
I hope this helps and that the material your daughter is entitled to is made accessible to her.