Regardless of what the law says--and yep, it's true, as most folks dealing with 504s know--parents do tend to be brought in on the team, as they are really one of the "variety of sources"* that is typically considered.
If you were on the team when the 504 eligibility was given, I would make a case to the school that nothing has changed to make you an unimportant source. Your input was a critical part of the variety of sources they used then--and it is now. So this is what CM recommended--I don't need to restate it.
If you are at a different school, then this tack may not be as effective. We moved--not only to a new district but to a new state--and the high school wanted to dispense with the 504 at our meeting. We won--and it wasn't much of a fight. It was clear I knew the law and I said we were not interested in getting rid of the 504 and only having an IHP. And they didn't balk after the meeting, which was lucky for us.
----------
I think it's time to start documenting. If you have been given this information--about the school wanting to remove accommodations--send a Letter of Understanding (LOU) to the school. It's factual and without emotion. You spell out what you understand has happened and ask them to clarify (by a certain date) if the circumstances are not as you have described them.
If they have also already indicated that they are planning to have a reevaluation without you present, note that as well, and in the LOU indicate why you are an important source and must be part of their variety of sources.
I know it's risky to give test results to school officials, but we have done it--and with good results. You may consider that here, if you have recent results. And you could even include that in your LOU and say, "DC's medical condition has not changed (assuming tests show that), and therefore his eligibility should not change either."
Some helpful links in case you need to review--especially in light of the new ADAAA:
http://www.nsba.org/SchoolLaw/Federal-Regulations/Archive/504-FAQs.htmlhttp://www2.ed.gov/about/offices/list/ocr/504faq.html*The Section 504 regulatory provision at 34 C.F.R. 104.35(c) requires that school districts draw from a variety of sources in the evaluation process so that the possibility of error is minimized.