Managers of logistics networks have the complex task of continuously maintaining their network in good operating conditions under a changing environment. Thus, they need to identify promising actions to adapt and improve the logistics network. Such actions could be the relocation of stock or the adjustment of transport relations. In order to support the managers, the authors have previously proposed a decision support system (DSS) based on discrete-event simulation (DES). The DSS automatically examines possible actions and suggests the best actions found to the managers. Since a data-driven DES approach is used for this DSS, all actions can be described as changes to a database. In this paper, an approach for modeling, integrating and executing user-generated actions into the DSS is described, in order to increase its flexibility and usability. In conclusion, the authors propose to develop a domain-specific modeling language for modeling actions for DES models.