Enable or Disable Event at instance, session or for another session in Oracle

Enable or Disable Event at Instance Level:

-- Enable at Instance Level:
ALTER SYSTEM SET EVENTS '<event> trace name context forever, level <level>';

-- Disable at Instance level:
ALTER SYSTEM SET EVENTS '<event> trace name context off';

Enable or Disable Event at Session level:

--Enable at session level:
ALTER SESSION SET EVENTS '<event> trace name context forever, level <level>';

--Disable at Session Level:
ALTER SESSION SET EVENTS '<event> trace name context off';

Enable or Disable event for other Session:

-- Enable for different Session
EXECUTE dbms_system.set_ev (sid,serial#,eventnumber,level,'');
Exmple: Session id 109 serial# 2456
EXECUTE dbms_system.set_ev (109,2456,10046,8,'');

--Disable the event for session:
EXECUTE dbms_system.set_ev (109,2456,10046,0,'');