SELECT temporary_acting FROM management WHERE temporary_acting != "Yes" UNION SELECT temporary_acting FROM management WHERE "department_ID" != 15 AND temporary_acting != "Yes" OR "head_ID" < 4 <table_name> : management col : department_ID | head_ID | temporary_acting row 1 : 2 | 5 | Yes row 2 : 15 | 4 | Yes row 3 : 2 | 6 | Yes row 4 : 7 | 3 | No row 5 : 11 | 10 | No <table_name> : management col : department_ID | head_ID | temporary_acting row 1 : 2 | 5 | Yes row 2 : 15 | 4 | Yes row 3 : 2 | 6 | Yes row 4 : 7 | 3 | No row 5 : 11 | 10 | No
col : temporary_acting row 1 : No