Operation marker for rejecting a previously proposed change. Rejection removes proposal state without applying the requested changes. It is used when a reviewer, participant, or policy decides that the proposed mutation should not become part of the document. Reject Change complements Propose Change and Accept Change. The operation itself declares the action; the paired Reject Change Workflow checks that proposal state exists and removes it through an Update Document step. If no proposal exists at the expected path, the workflow emits Proposed Change Invalid.