Question, questions!
If your child has an IEP (Individualized Education Program) through the school, they are eligible for certain special-ed services. The only problem is, the schools only have to provide an "appropriate education" under the law. What the school finds "appropriate' and what the parent finds "appropriate" are usually completely different. The IEP grants certain accommodations for the child, and by law, the school is expected to uphold them. The 504 holds less clout, than an IEP.
A parent is allowed to request an emergency IEP meeting at any time. The parent also has a right to ask that their child have certain evaluations done by the school. This can include an OT or Speech Evaluation, but this does not guarantee that the child will be approved for therapy. Actual ASD evaluations are done by private professionals, NOT the school.