[SQL] Column Specific Update Trigger Routine

[Plugge, Joe R.]

I am trying to create a update trigger on a table that basically will only fire 
when a specific column is updated.  I am using version 8.4.3.

My plan of attack was to always fire on any row update, and pass in the OLD and 
NEW column that I want to check.

CREATE TRIGGER check_lockout
    AFTER UPDATE ON acct_table
    FOR EACH ROW
    EXECUTE PROCEDURE 
acct_unlock(OLD.userid,OLD.ownerid,OLD.password,NEW.password);


This fails with :

[postg...@linux1505 ~]$ cat check_lockout_trig.sql | psql testdb
ERROR:  syntax error at or near "OLD"
LINE 4:     EXECUTE PROCEDURE 
acct_unlock(OLD.userid,OLD.ownerid,OLD.password,NEW.password);


What am I doing wrong? Or is there a better way to go about this?