Migrating heterogeneous high-performance computing (HPC) systems to resource-aware scheduling introduces both technical and behavioral challenges, particularly in production environments with established user workflows. This paper presents a case study of transitioning a production academic HPC cluster from node-exclusive to consumable resource scheduling mid-lifecycle, without disrupting active workloads. We describe an operational strategy combining a time-bounded compatibility layer, observability-driven feedback, and targeted user engagement to guide adoption of explicit resource declaration. This approach protected active research workflows throughout the transition, avoiding the disruption that a direct cut-over would have imposed on the user community. Following deployment, median queue wait times fell from 277 minutes to under 3 minutes for CPU workloads and from 81 minutes to 3.4 minutes for GPU workloads. Users who adopted TRES-based submission exhibited strong long-term retention. These results demonstrate that successful scheduling transitions depend not only on system configuration, but on aligning observability, user engagement, and operational design.