Here is a little script to rename items quickly.  Just provide a CSV file with old and new item number.  I found that making the CSV file was faster than making a job to intelligently rename items because I could use Excel functions and review the new item numbers faster.

static void renameFromCSV(Args _args)
{
#File
CommaIO file;
Container values;
Dialog dialog;
DialogField dfFileName;
LineNum lineNum;
ItemID itemIDfrom;
ItemID itemIDto;
InventTable inventTable;
;
setPrefix(funcName());
dialog = new Dialog("Rename items");
dialog.filenameLookupFilter(["@SYS39829", #AllFilesName + #csv]);
dfFileName = dialog.addField(typeid(FileNameOpen));
if (!dialog.run() || !dfFileName.value())
return;

if (!WinAPI::fileExists(dfFileName.value()))
throw error(strfmt("@SYS18678", dfFileName.value()));

file = new CommaIO(dfFileName.value(), #io_read);
if (!file)
throw error("@SYS74299");
values = file.read();

while (values != connull())
{
setPrefix(strfmt("Row %1 for %2", lineNum, conpeek(values, 1)));
if (conlen(values) != 2)
throw error('Bad row');

itemIDfrom = conpeek(values, 1);
itemIDto = conpeek(values, 2);

if (InventTable::exist(itemIDfrom))
{
if (!InventTable::exist(itemIDto))
{
ttsbegin;
inventTable = InventTable::find(itemIDfrom, true);
inventTable.ItemId = itemIDto;
inventTable.renamePrimaryKey();
ttscommit;

info(strfmt("%1 to %2", itemIDfrom, itemIDto));
}
else
error(strfmt("@SYS93964", itemIDto));
}
else
error(strfmt("@SYS94719", itemIDfrom));

lineNum++;
values = file.read();
}
info("@SYS78985");
}