This example shows what a call to UnRegisterDynamicSource looks like. Refer to ISystemDebugEventInstall Example (Visual C++) to see the constant declarations and object creation code, as well as to see this code in a form you can run with minor modifications.
// Unregister the dynamic component.
void SampleUnRegisterDynamicSource()
{
pESI->UnRegisterDynamicSource( SAMPLE_DYNAMIC_SOURCE_GUID );
}