The numerous reform interventions that have followed one another in a more or less incisive manner over the discipline of the service conference have profoundly changed the original features of the institute. On 28 July 2016 the Legislative Decree no. 127 of 2016 which, perhaps, has completed this long process of transformation that has changed the services conference from a coordination tool into a decision tool in an attempt to remedy those critical issues never resolved. The model of services conference prior to the 2016 reform has not been able to provide a valid response to the increasingly pressing needs of simplification and, paradoxically, has generated an excessive administrative burden. The new service conference seems to be able to respond to the constant requests for simplification and coordination. The paper moves from a concise reconstruction from the diachronic point of view of the service conference institute, to focus on the main legislative innovations dedicated to the services conference in its most relevant expression, c.d. decisive, and understand the change from a functional point of view.