The complexity of social systems is characterized by the possible occurrence of simultaneous or sequential processes of structural change. This paper is focused on certain types of structural change: (i) those produced by assembly and disassembly and (ii) those resulting from decisional and/ or behavioral processes, including both bottom-up and top-down processes. These general concepts from system theory are applied to the case of Indonesia's decentralization. The well-known story of Indonesia's remarkable transition to a democratic society and decentralized nation is presented here in an alternative manner that has allowed us to identify types of structural changes in empirical events. Ultimately, this analysis offers a better explanation of the intrinsic complexity of any social organization and demonstrates an approach to similar problems.