Eruptive style transitions and pattern of cyclicity in eruptive activity have become among the main challenging topics in present-day volcanological research. This is because their understanding is relevant for both physical description of volcanic phenomena and hazard mitigation plans. Complex eruptive cycles and alternating eruptive styles have been frequently observed inmost volcanoes worldwide, but they are far from being fully understood. In the last few years, new efforts have been devoted to better constrain some physical variables controlling changes in eruption dynamics (i.e. changes in local and far field stress, geometrical evolution of the conduit feeding system). In addition, many magmatic/volcanic processes can also be characterized by patterns of cyclicity during both effusive and explosive eruptions. These include variations in lava effusion rates, gas flux, ground deformation, seismicity as well as any temporal change in the properties of the magma-chamber-conduit system. For this reason, analyzing and modeling these patterns during volcanic activity is fundamental to understand eruptive dynamics and to evaluate current hazards and future scenarios. In this session, we encourage contributions focused on evidence of both eruptive style transitions and increasing, decreasing, stationary,and cyclic eruptive activity, collected by using either single parameter or multi-parametric approaches. The combination of field data, ground-and satellite-based measurements, and numerical modeling are welcome, with special emphasis to the correlation between internal processes, occurring inside the volcano plumbing system, and external phenomena, observed at/above the vent.