What do you mean by "is not reindexed after APPEND"?

>The follow are the coding I have created... the question is how come the WORKPO.DBF is not reindexed after APPEND?
>
>leavenow=.F.
>SET ESCAPE OFF
>SET MULTILOCKS ON
>ON ERROR DO getout
>LOCAL laTables, lcTableName, lcKey
>OPEN DATABASE encum EXCLUSIVE
>DIMENSION laTables[1]
>ADBOBJECTS(laTables, "TABLE")
>FOR EACH lcTableName IN laTables
> USE (lcTableName) EXCLUSIVE IN 0
> IF leavenow=.T.
> CLOSE ALL
> EXIT
> ENDIF
> SELECT (lcTableName)
> lcKey=DBGETPROP(lcTableName, "TABLE", "PrimaryKey")
> SET ORDER TO &lcKey
>ENDFOR
>
>IF leavenow=.T.
> RETURN
>ENDIF
>SET ESCAPE ON
>ON ERROR
>
>*the remaining of the program starts right here...
>SELECT poencr
>APPEND FROM poencr.xls TYPE XLS
>GO TOP
>DELETE
>PACK
>SELECT workpo
>APPEND FROM poencr
>REPLACE ALL date WITH DATE()
>REPLACE blanket WITH "40" FOR blanket = "GEN"
>REPLACE blanket WITH "43" FOR blanket = "BLK" OR blanket = " "