Requirements elicitation is a highly relevant part of the software development process. Due to the several techniques that exist to perform it, it is necessary to understand the complexity of this activity for it to be well performed, thus ensuring the quality of the final product. In addition, it is also worth emphasizing that the existence of well-defined processes is essential for the stakeholders' needs to be correctly identified in the initial stages of the software development process. This paper presents an experience report of the requirements elicitation and business process modeling teams. The teams used the best practices and reference frameworks to understand, model, and perform business process enhancements to the Brazilian Unified Health System General Audit Office (AUDSUS) audit system by using the business process model and notation (BPMN). Thus, all software requirements were specified based on the modeled business processes, providing a faster software development process and a more efficient information flow between stakeholders and the teams involved.