This paper seeks to identify critical events and factors that facilitate realization of changes in production. Major planned changes were studied in two industrial cases. The results showed a large number of unpredicted critical events which require development of strategies for both minimizing and coping with uncertainties. The most important facilitators for realization of planned changes in production were related to organizational and human aspects, and to a lower degree technology aspects. In the transition from the preparation phase to the implementation phase of the planned change, factors related to organizational aspects dominated, while factors related to human aspects had increased significance for the overall realization.