According to IIA guidance, if management refuses to accept audit recommendations and implement corrective actions, the chief audit executive (CAE) has a responsibility to ensure that the audit committee or the board is aware of the unresolved risks. The CAE should escalate the matter to senior management first. If senior management still does not take action, the CAE should then inform the board. This escalation process ensures that the board is fully informed about significant risks that management has decided to accept and can take appropriate action if necessary.
Reference:
The Institute of Internal Auditors (IIA) - Standards for the Professional Practice of Internal Auditing, Standard 2600 - Communicating the Acceptance of Risks