Change Oracle Apps password from Backend

SET SERVEROUTPUT ON;

DECLARE
      flag BOOLEAN;
BEGIN
      flag := fnd_user_pkg.changepassword(username=> 'MY_USER'
                                          ,newpassword => 'welcome1');
    IF flag
     THEN
           DBMS_OUTPUT.PUT_LINE('Your Password has been successfully reset');
     ELSE
           DBMS_OUTPUT.PUT_LINE('Password reset has failed');
     END IF;
END;
/
COMMIT;