Table schema:
CREATE TABLE table_name_24 (date_of_vacancy VARCHAR, team VARCHAR, date_of_appointment VARCHAR)

Question: What is the date of vacancy of team fc bayern munich, which had a date of appointment on 27 April 2009?
SQL: SELECT date_of_vacancy FROM table_name_24 WHERE team = "fc bayern munich" AND date_of_appointment = "27 april 2009"