What are the conditions for Australian parents to change their visa from 173 to 143?

173 application conditions for immigrant residence visa for parents' reunion: guarantor requirements: 1) Australian citizen, permanent resident or qualified New Zealand citizen; 2) 18 years old or older (including 18 years old); 3) No crime; 4) Have certain economic guarantee ability; 5) Have lived in Australia legally for at least two years. 143 application conditions for permanent residence visa for parents' reunion immigrants: guarantor requirements: 1) Australian citizens, permanent residents or qualified New Zealand citizens; 2) 18 years old or older (including 18 years old); 3) No criminal record; 4) Have certain economic guarantee ability; 5) Have lived in Australia legally for at least two years.