If the Chief Audit Executive (CAE) disagrees with management's decision to deem certain action plans no longer necessary, the CAE must discuss the matter with the board. The board has the ultimate responsibility for oversight of the internal audit function and for ensuring that management addresses audit recommendations appropriately. Escalating the issue to the board ensures that the CAE fulfills their duty to report significant issues and disagreements to those charged with governance.
Reference:
The Institute of Internal Auditors (IIA) Standard 2600 - Communicating the Acceptance of Risks: "When the chief audit executive believes that senior management has accepted a level of residual risk that may be unacceptable to the organization, the chief audit executive must discuss the matter with senior management. If the decision regarding residual risk is not resolved, the chief audit executive must report the matter to the board for resolution."