The simplest way to replace an item’s barcode is to use the Replace Barcode function on the Circulation drop down menu. You will be prompted to enter the old barcode and then the new barcode.
Replace Barcode function is also available on the Holdings Maintenance screen.
The Edit function (the link beside item’s barcode) on Record Details screen on the catalogue allows you to update barcode, too.
You may also replace a barcode on the Item Status (F5) screen.
For more information including a video see http://docs.libraries.coop/sitka/_replacing_a_barcode.html