The SSA-3373-BK form is used to report any changes that have occurred in your medical condition or work history since the time of your application. What exactly constitutes a change depends on whether you have been approved as disabled, denied benefits, or are still awaiting a decision. The information you reported in this form will be compared to your initial application or last review. The changes you note may affect whether or not your disability claim is approved again, denied benefits altogether, or if additional information is required.