DATA: it_bname TYPE xubname OCCURS 10
    , return TYPE bapiret2 OCCURS 1
    , BAPIPWDX type BAPIPWDX value 'X'
    , BAPIPWD type BAPIPWD value '12345'
.
FIELD-SYMBOLS: <bn> TYPE xubname.
SELECT bname
   INTO TABLE it_bname
   FROM usr02
   WHERE erdat = '20061103'
      AND aname = 'MYNAME'
   .

LOOP AT it_bname ASSIGNING <bn>.
  CALL FUNCTION 'BAPI_USER_CHANGE'
    EXPORTING
      username  = <bn>
      password  = BAPIPWD
      passwordx = BAPIPWDX
    TABLES
      return    = return.
ENDLOOP.

COMMIT WORK.