You can modify existing parametric parts with Content Builder. For parts in the catalogs provided by AutoCAD MEP 2024 toolset, you can change the part behavior, part size parameters, and connectors. For parametric parts you create using Content Builder, you can change the part behaviors, part size parameters, connectors, and part model including geometry, profiles, modifiers, constraints, and dimensions. You can also delete parts that you no longer need. Deleting parts can be helpful when creating custom catalogs to ensure that all associated definition files are managed correctly.