customize the workflow notification output EBS

I used this pakage ( wf_notification) to send a workflow notification in EBS.

declare

 nid number;

 msg_type varchar2(100) := 'WFTESTS';

 msg_name varchar2(100) := 'PLSQL_MSG';

 role varchar2(320) := 'SLPAUSER';

begin

  nid := wf_notification.send(role, msg_type, msg_name);  

  commit;

end;

OUTPUT MESSAGE "PLSQL Message for Testing Workflow Notification Mailer " IS THIS. I WANT TO CUSTOMIZE THIS