Rename or recolor an existing tag in the user’s personal set or their team’s shared set. The tag’s id is preserved, so the change is reflected everywhere the tag is already applied — no item loses the tag. Provide the tag’s id and its set’s property_definition_id (both from ListTags) plus a new label and/or color; omit whichever you want to leave unchanged. This edits the tag itself; to change which tags are on a specific item, use SetEntityProperty instead.