Laurie De Vito is a dancer by trade, a longtime Brooklyn resident who teaches contemporary modern dance at studios around the city.  But as the mother of an 18-year-old with a disability, she also has nearly two decades of experience banging on doors to make sure her son receives the services to which he is entitled.  This year, her skills as a mother-bear advocate met their greatest challenge and most rarefied audience. Through sheer force of will, she found herself on the phone with the highest education officials in the state — including the chancellor of the Board of Regents and the commissioner of the Department of Education — lobbying them to make changes to state policy that would allow her son to earn his high school diploma. And it is working.  “Don’t be intimidated by these people,” Ms. De Vito said. “There’s no do-over with my kid.”  Her son, Dylan Cunningham, has been receiving special education and intervention services since he was about 2, Ms. De Vito said. He developed late, and when he entered kindergarten, he was still not speaking in sentences. He has had difficulty with speech and language ever since.  Today, he is in a program for students with learning disabilities at Bay Ridge Prep, a private school in Brooklyn. A skinny teenager with short brown hair, he likes to play jazz and rock ’n’ roll on his red Gibson guitar, and he would like to work with animals one day. When he stands near his mother, his hand finds a comfortable place on her shoulder.  Advocates for children with disabilities say that parents engage in a constant battle to ensure their children get the services they require, and those they have already been promised.  “Having a kid with differences, you have additional responsibilities,” said Lori Podvesker, manager of disability and education policy at INCLUDEnyc, and the mother of a boy with special needs. “Every day, you have a list of 20 things you need to do, and everything has 10 components.  “For me as a parent, every day I’m thinking about my list,” she said. “You have to be tenacious.”  While there are exceptions, students in New York are generally required to pass five Regents exams with a score of 65 or higher to graduate from high school, while students with a documented disability can pass with a score of 55. Though it is a private school, Bay Ridge Prep, which Mr. Cunningham attends, uses those same requirements.  He came close to meeting them. He has made tremendous strides in academic performance and behavior, according to faculty members at the school. He has passed four Regents exams, with scores as high as a 79, but on his algebra exam, he tried three times and his highest score was a 54. He was short by one point.  If students come within three points of their passing score of 65, they are allowed to appeal, so long as they satisfy other requirements — a high rate of attendance and passing the class, for example. But the same appeal is not available to students with disabilities who are aiming for that lower passing score. So when Ms. De Vito received her son’s score this summer, she snapped into action.  “He’s not going to graduate high school over one point?” Ms. De Vito recalled. “This is a high school diploma. If he doesn’t get it, he can’t collect sanitation.”  “My kid,” she continued, tightly clenching her fists, “is a success story.”  She looked up phone numbers for the state’s Education Department and started dialing. The first person she spoke with did not provide an encouraging start.  “She said that Regents are embedded in New York for the last 100 years; you’re not going to change it,” Ms. De Vito recalled. “And I said, ‘O.K., well let’s agree to disagree, and give me somebody else to talk to.’”  She made more phone calls and sent out batches of emails detailing Mr. Cunningham’s story, addressing them to members of Congress and the State Legislature, as well as to Merryl H. Tisch, chancellor of the Board of Regents.  “At 6 p.m. on a Thursday night, I come home from a meeting, my phone rings, and it’s Merryl Tisch,” Ms. De Vito said. “She said, ‘I received your letter,’ and she said, ‘It made me want to cry.’”  Within a few weeks, Ms. De Vito had conversations with several high-ranking education officials, including Kathleen M. Cashin, the regent who represents her borough, and the state education commissioner, MaryEllen Elia. In September, a new rule that would allow an appeal for special education students who score at least a 52 was proposed at a Regents meeting. The board is likely to vote on it in December.  “Certainly she was a great advocate for her child,” Ms. Elia said in an interview. “It helped us clarify and look at a number of regulations to make sure there’s equity there for our students with disabilities.”  Though the idea of removing an obstacle to graduation may sound to some like a lowering of standards and expectations for students with disabilities, Ms. Tisch was quick to bat away such concerns.  “We do not want schools to offer these kids less,” Ms. Tisch said. The goal, she said, is to figure out “how do you include these students in the raising of the standards without diminishing their ability to achieve at their own level?  “How do you not write them out of the script of high achievement?”  Michael Dealy, the head of school at Bay Ridge Prep, said that as a private school, Bay Ridge has some discretion in its graduation requirements, and it has made three or four exceptions to the state specifications since it was founded 17 years ago. And if Mr. Cunningham continues on his current path, Mr. Dealy said, he seems likely to get his Bay Ridge Prep diploma no matter what the Regents decide.  “I would say so,” Mr. Dealy said. “Wouldn’t you graduate him?”  A version of this article appears in print on October 20, 2015, on page A20 of the New York edition with the headline: Woman Takes Fight to Top Education Officials After Disabled Son Misses Graduation by a Point . Order Reprints| Today's Paper|Subscribe
New York State students who come within three points of passing a Regents exam can appeal in certain cases, but that option isn’t available to some disabled students.