If you want to expand the ontology, you can add a new concept that represents an entirely new clinical meaning, or refines the meaning of an existing concept with new descriptions or relationships. You are only allowed to edit a concept's core properties like status and definition status, its descriptions, and source relationships. Destination relationships and Reference Set memberships are read-only; you can use the Reference Set Editors to add and remove Reference Set members. Editing is strongly limited for released components; the limitations will be described in more detail in the sub-sections.