CREATE TABLE table_26646 ("State  ( class ) " TEXT, "Vacator" TEXT, "Reason for change" TEXT, "Successor" TEXT, "Date of successors formal installation" TEXT)

Who was the vacator when the successor was formally installed on February 1, 1871?
SELECT "Vacator" FROM table_26646 WHERE "Date of successors formal installation" = 'February 1, 1871'
SELECT "Vacator" FROM "table_26646" WHERE "Date of successors formal installation" = 'February 1, 1871'