Patients can make a complaint to OCR about any type of HIPAA violation – for example, the failure to provide a Notice of Privacy Practices, the failure to comply with a restrictive access request (i.e., restricting who PHI is disclosed to), and the failure to contact them by a pre-requested communication channel (i.e., contacting a patient by voice message rather than SMS). It is also the case that a patient can make a non-specific complaint about a HIPAA violation by a covered entity. For example, a patient might share a unique identifier with a hospital, only to find out the identifier has been leaked. The patient knows a HIPAA violation has occurred because no-one else has access to the identifier, but doesn´t know the specific circumstances of the violation.