A social revolution is the transformation of a mode of production into another mode of production. It involves first of all the negation of the existing relations of production as a result of a conflict with the level of the material productive forces in society. The relations of production are then replaced by new ones on the basis and consistent with the level of the productive forces. The new relations of production on the basis of the productive forces dictate the methods of distribution (the economic base), and from the basis of the new relations of production emerges a superstructure. 
Negation of the negation
After the initial revolution, Marxists believe that a second process occurs called the negation of the negation, where the new mode of production, which was first an active negation of the earlier one, begins operating according to its own internal social laws. For example, a bourgeois revolution might at first give everyone the status of free burghers with ownership of their labour, but this first negation of the feudal order then settles down and gains its own dynamics, leading into the class structure of capitalism. Similarly, a socialist revolution will also have two such moments. At first, it is the active negation of the bourgeois class within the economy. This is moment called the dictatorship of the proletariat. After this, however, workers will need to develop a self-sustaining social order without class hierarchy.
Kinds of revolution
In the bourgeois social revolution, the relations of production are transformed from feudal bonded labour to wage-labour. In the era of proto-industrialisation from the sixteenth century onwards, bonded labour had been partially replaced by a working class owning the instruments of its labour. As consequence of the industrialisation, the working class was transformed into the proletariat with market forces compelling the working class to selling their labour-power to an owner of machinery. The relations of production (wage-labour) determine the mode of distribution (commodity exchange). This brought forth a conflict between the bourgeoisie and nobility and the modern state (as well as bourgeois democracy) arose from the economic base.
In capitalism there exists a fundamental contradiction between socialised labour and capitalist appropriation, the source of class conflict between the proletariat and the bourgeoisie. The socialised labour, moreover, is executed as private between separate enterprises. Consequently, the social character of labour becomes only social indirectly through the exchange of commodities.
A socialist revolution would begin with the transformation of the relations of production, with workers seizing control over their workplacing and authorising territorial workers' councils or other organs of workers' power, providing the working class with political power. The superstructure, the dictatorship of the proletariat, arises out of the newly forming relations of production of association. As the new relations of production based on associated labour expand and consolidate, the social character of labour is directly expressed, and commodity exchange, and therefore value, the value-form, and the law of value, wither away, reaching the communist mode of production.
- Marx: "In the social production of their existence, men inevitably enter into definite relations, which are independent of their will, namely relations of production appropriate to a given stage in the development of their material forces of production. The totality of these relations of production constitutes the economic structure of society, the real foundation, on which arises a legal and political superstructure and to which correspond definite forms of social consciousness. The mode of production of material life conditions the general process of social, political and intellectual life. It is not the consciousness of men that determines their existence, but their social existence that determines their consciousness. At a certain stage of development, the material productive forces of society come into conflict with the existing relations of production or – this merely expresses the same thing in legal terms – with the property relations within the framework of which they have operated hitherto. From forms of development of the productive forces these relations turn into their fetters. Then begins an era of social revolution. The changes in the economic foundation lead sooner or later to the transformation of the whole immense superstructure." Preface to A Contribution to the Critique of Political Economy