Substantial or non-substantial change of machinery according to Machinery Directive 2006/42/EC

More and more machine manufacturerer but also operator are confronted with remodelling of old machinery or plants as well as the assembly of old machinery in new plants. The judicial surroudings into which you get is not instantly clear for everybody.
When is a remodelling a "Substantial Change" according to the Machinery Directive 2006/42/EC, which duties does it bring along for the manufacturer?

Document of interpretation (essay) of the german "Bundesanstalt für Arbeitsschutz und Arbeitsmedizin" [german]

Download:
Interpretationspapier_GSGV.pdf

see also external link:  Interpretationspapier "Wesentliche Veränderung von Maschinen"  [german]