In application, Giddens is separating himself from other structuralists by acknowledging the enabling functions that the structure provides.
In this respect the structure is imposing restrictions upon the agent in order to accomplish societal norms.
Norms, however, have changed in the past and are under constant manipulation by the society through the use of structural "resources".
Laws that have limited human liberties, can be overturned as there exists "resources", e.g. lawyers who can present a case for social reform.
Giddens suggests that it is these modalities that illustrate his reliance on the duality of structure because it presents a case where knowledgeable individuals can use the resources available to them to change policies, standards or norms that the structure imposes upon them.