ad_zd.ALTER_LOGON_TRIGGER('DISABLE');

SQL> col owner format A8

SQL> col trigger_name format A14

SQL> select owner, trigger_name, status from dba_triggers where owner = 'SYSTEM' and trigger_name = 'EBS_LOGON';

OWNER TRIGGER_NAME STATUS

-------- -------------- --------

SYSTEM EBS_LOGON ENABLED

SQL>