The goal of the paper is building the knowledge-based model for predicting the state of the IT support organization. These organizations are facing the problem of their transformation. The complexity of the processes, the difficulty adjusting the operations and limited ability to control the evolution implies the need of the solutions supporting the decision-makers to make the change happen. The solutions are based on systems gathering and processing the knowledge, built in the research units for the support of business organizations. The paper is the example of the applying this research for the banking sector. The result of the research is the intelligent, knowledge-based system used for the assessment of the organization and support the evolution of the organizations based on fuzzy modeling and mechanisms of reasoning using uncertain and incomplete knowledge and classification according to the ITIL (IT Infrastructure Library) model. The sources of the knowledge are the authors’ experiences in managing the IT support organization in the banking sector. The paper presents the results in two areas. One of them is the financial sector, for which we propose the prognostic model for the IT support organization. The second is the selection of reasoning in social systems with uncertain and incomplete knowledge. In the paper we present the mechanisms of reasoning based on the knowledge and data in the research in the evolution of the IT support organization in the financial institution. The publication contains the description of the assumptions of the experiment, the experiment itself, the analysis of its results and conclusions.