Although transitions are usually perceived as technological substitution processes, the article shows that stepwise reconfiguration is more likely for supplier-dominated sectors. In this transition pattern, novelties are initially adopted as 'modular innovation' into existing systems and subsequently reconfigure the basic architecture through new combinations of old and new elements. Incumbent actors survive these transitions through interactions with suppliers of knowledge and innovations. Using Pavitt's innovation typology, we selected a case study from his supplier-dominated category: greenhouse farming. The article makes a techno-economic analysis of the overall transition pattern in Dutch greenhouse horticulture (1930-1980) and a socio-institutional analysis of the knowledge flows and networks. 'Innovation cascades' are identified as a particularly important mechanism in reconfiguration transitions.