CREATE TABLE table_3009 ("District" TEXT, "Vacator" TEXT, "Reason for change" TEXT, "Successor" TEXT, "Date successor seated" TEXT)

Name the reason for change when George W. Greene (D) was the vacator.
SELECT "Reason for change" FROM table_3009 WHERE "Vacator" = 'George W. Greene (D)'
SELECT "Reason for change" FROM "table_3009" WHERE "Vacator" = 'George W. Greene (D)'