MCReNet is a tool for the specification, modeling, simulation, and verification of concurrent systems that are subject to dynamic changes by using Marked-Controlled Reconfigurable Nets. In a marked-controlled reconfigurable net, a system configuration is described as a Petri net and a change in configuration is described as a graph rewriting rule. A change in configuration amounts to a modification in the flow relations of the places in the domain of the involved rule in accordance with this rule, independently of the context in which this rewriting applies. The enabling of a rule depends on the net topology and on the net marking according to control places.