Recently, the design and development of multiagent systems (MASs) has become increasingly concerned with the recognition that they will be used in a dynamic and open environment. In such environments, it is a very difficult and complicated task to anticipate all possible runtime situations at design time. Therefore, in order to respond to changes in this environment it is necessary to allow the system to provide dynamic responses at runtime. This thesis is concerned with one particular aspect of such responses. Our novel contribution is that we explicitly identify clarify and address the problem of dynamic assignment of rights, responsibilities (R&Rs) and sanctions to external agents in normative MASs.