Mayo Clinic Health System — Southwest Minnesota Region, one of four practice regions in the Midwest, provides primary and speciality care in ambulatory, procedural and hospital settings. Clinic appointment fill rates, no-show rates and late cancellation rates are closely monitored operational metrics, but at the time this study began, less was known about the refill rates of late appointment cancellations. This metric is of importance because these unfilled appointment times contribute to increased expenses for healthcare organisations, unnecessary delays in care and decreases in revenue. The main objectives of this study were to understand the current state and potential opportunities for refilling late cancellations. Qualitative and quantitative methods were used, including variance analysis, the Tukey post hoc test, Pareto analysis, the completion of interviews with important stakeholders and data extraction from the institution’s electronic health record. Findings showed that late cancellation rates remained steady in 2021 and that late cancellations were not being refilled consistently across departments and regions. Appointment refill rates were higher in departments with few or no requirements for preparatory evaluation, whereas in specialties that did require preparatory evaluations, refill rates were lower across the four regions of the Mayo Clinic Health System. Even in departments with high demand, the refill rates were lower, resulting in missed opportunities for patient visits. Mapping the workflow for late cancellations indicated inconsistent methods for refilling late cancellation openings and the lack of a defined process for refilling them that was understood by the entire care team. The logistics of optimising refill rates for late cancellations were affected by provider preference, selfscheduling functionality and appointment requirements. This study identified opportunities for optimising workflows to use the waiting list proactively to refill late cancellations.