FIELD-SYMBOLS: <fs_vbap>  TYPE any,
                 <fs_werks> TYPE any.

    UNASSIGN: <fs_vbap>, <fs_werks>.
    ASSIGN ('(SAPMV45A)XVBAP') TO <fs_vbap>.
    IF <fs_vbap> IS ASSIGNED.
      ASSIGN ('<fs_vbap>-werks') TO <fs_werks>.
      IF <fs_werks> IS ASSIGNED.
*----- Aqui sua lógica
      ENDIF.
    ENDIF.