If you look at the law about the Local Government Act 1974, you will see a part called 'Extraordinary vacancies'. You can find this in section 5, but it is no longer part of the law because it was repealed. This means it was removed from the law on 1 April 1990 by a change made in the Local Government Amendment Act (No 2) 1989, which you can read more about by following the link to section 4(1). You can still learn about what this section used to say, but it does not apply anymore. The law changed and this part is not used now.