Define 'out' parameters
SQL> SQL> create or replace 2 procedure swap( p_parm1 in out number, p_parm2 in out number ) as 3 -- 4 l_temp number; 5 begin 6 l_temp := p_parm1; 7 p_parm1 := p_parm2; 8 p_parm2 := l_temp; 9 end swap; 10 / SQL> SQL> SQL>