Special Needs Plans Reauthorization Act of 2017 or the SNP Reauthorization Act of 2017 (Sec. 2) This bill allows a Medicare Advantage (MA) plan, until 2024, to restrict plan enrollment to certain special-needs individuals, provided that the plan meets specified applicable requirements. Current law allows an MA plan to do so until 2019. The Federal Coordinated Health Care Office within the Centers for Medicare & Medicaid Services (CMS) shall serve as a dedicated point of contact for states with regard to special-needs MA plans for individuals who are dually eligible for Medicaid and Medicare. The CMS shall establish a unified process for grievances and appeals for individuals enrolled in such plans. The CMS must, with respect to special-needs MA plans for individuals with chronic conditions, convene a panel of clinical advisors to establish and update the list of chronic conditions that make an individual eligible for participation in such a plan. The Government Accountability Office (GAO) must study and report to Congress on health outcomes of individuals enrolled in specialized MA plans. The CMS shall, with respect to special-needs MA plans, consider applying certain quality measures at the plan level rather than at the contract level. The GAO must report to Congress on state-level integration between the Medicaid program and special-needs MA plans for individuals who are dually eligible for Medicaid and Medicare. (Sec. 3) Beginning in plan year 2020, an MA plan may provide certain supplemental benefits to chronically ill enrollees. The GAO must report to Congress on the provision of such supplemental benefits to MA enrollees.