You should always make the change at the highest appropriate level — this will then filter down to the subdivisions and all attached bibliographic records. You can see this in the example below.

 

If you changed the heading “§aAborigines, Australian” to “§aAboriginal Australians” then all other authority headings which use that term would be changed, and all the attached bibliographic records would be updated.

However, if you changed the heading “§aAborigines, Australian§xAgriculture” to “§aAboriginal Australians§xAgriculture” then:

• A new heading of “§aAboriginal Australians” would be created.
• A new heading of “§aAboriginal Australians§xAgriculture” would be created. Attached to this heading would be the bibliographic records previously attached to “§aAborigines, Australian§xAgriculture”.
• “§aAborigines, Australian§xAgriculture” would be deleted as there are no longer works attached.
• “§aAborigines, Australian” would still exist as there are other works and headings attached.