CREATE TABLE table_46755 ("Team" TEXT, "Outgoing manager" TEXT, "Manner of departure" TEXT, "Date of vacancy" TEXT, "Replaced by" TEXT, "Date of appointment" TEXT, "Position in table" TEXT)

What was the manner of departure for the vacancy date of 20 September 2009?
SELECT "Manner of departure" FROM table_46755 WHERE "Date of vacancy" = '20 september 2009'
SELECT "Manner of departure" FROM "table_46755" WHERE "Date of vacancy" = '20 september 2009'