user: Question: When was the date of vacancy for the manager of Kartalspor? 
Columns: ['Team', 'Outgoing manager', 'Manner of departure', 'Date of vacancy', 'Replaced by', 'Date of appointment']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Karşıyaka', 'Erdoğan Arıca', 'Mutual consent', '01 Sep 2010', 'Kemal Kılıç', '07 Sep 2010']
SQL:

assistant: SELECT "Date of vacancy" FROM "Table" WHERE "Team" = 'Kartalspor';