Mass Update line number in BPA in Production

Hi,

We have a requirement to mass update BPA line numbers of all existing lines of BPAs (with and without PO released lines) in Production.In FBDI only add option is there.The volume of BPA and BPA lines is huge. Can you suggest all the possible options which implementation/support team can do to achieve this without VBCS option?VBCS is too complex and as it at user end this can't be used