Our expansive pediatric primary care network includes 31 offices serving over 250,00 patients across Pennsylvania and New Jersey. Telephone nurse triage services are provided 24 hours per day. A centralized call center provides nurse triage services whenever network offices are closed. In contrast, a decentralized model of registered nurses working within the individual offices provides triage services during the daytime hours when offices are open. In fiscal year 2022, approximately 400 triage nurses spread throughout the primary care network managed over 400,000 triage calls. Previous work found that our decentralized model of daytime triage resulted in considerable variability in the way services were being delivered across the network. A telephone triage training class was developed as one intervention aimed at decreasing variability and standardizing nurse triage practice across the network. At its inception in 2016, the triage training class was offered quarterly and consisted of two full classroom days at a central urban location. The class design was approximately 75% lecture and 25% active learning. Post-class surveys consistently cited the need for more hands-on activity and access to the lecture content outside of class. The considerable time out of the office had been cited as a barrier to attendance, and the cadence of the class resulted in those in attendance being at varying stages of triage training. Identifying these opportunities for improvement led to a redesigned “office hours telephone triage training program,” a formalized approach to triage training implemented in April 2022. The program redesign aims to provide training in a format that meets the needs of the learner and the offices while ensuring consistency. The training occurs in four phases, with the cadence of the training class now occurring bimonthly. The content and structure are standardized and coordinated by program leaders. The two-day classroom training session has been replaced with a hybrid training course steeped in adult learning theory. The evidence-based flipped classroom was implemented to provide knowledge-based lecture content as pre-work. Students receive a “triage training workbook,” an online notebook designed to encourage student engagement and collaboration. Classroom time has been reduced to one full day and reserved exclusively for engaging, student-centered learning activities such as simulations, role play and scenario practice, and group discussion. Post-class evaluations have yielded positive feedback for this new model of triage training. Comparison of pre- and post-test scores indicate that our learning objectives are being met. After attending this poster presentation, the audience will understand how to use their organization’s existing technology and resources and apply it to the design of their own "flipped Classroom." They will be able to describe how to use readily available online collaboration tools to provide a shared learning space and centralized location for course materials. Participants will also understand how incorporating the principles of adult learning theory in class design can improve learner engagement and satisfaction with their training experience, and result in improved outcomes for their learners and their training programs.