CREATE TABLE table_11207040_6 (date_of_appointment VARCHAR2, outgoing_manager VARCHAR2)

What are the dates of the outgoing manager colin hendry does appointments?
SELECT date_of_appointment FROM table_11207040_6 WHERE outgoing_manager = "Colin Hendry"
SELECT "date_of_appointment" FROM "table_11207040_6" WHERE "Colin Hendry" = "outgoing_manager"