CREATE TABLE table_47900 ("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 date of vacancy after the outgoing manager, ralf santelli departed?
SELECT "Date of vacancy" FROM table_47900 WHERE "Outgoing manager" = 'ralf santelli'
SELECT "Date of vacancy" FROM "table_47900" WHERE "Outgoing manager" = 'ralf santelli'