I haven't explored the implications, but I have the gut feeling that Alter might provide a solution, since with that inside-out package objects don't loose their attributes on re-blessing and re-blessing back. Since @ISA is package (class) level, you might need to provide an equivalent method dispatch path on the object level, hard to tell without seeing the whole picture. But the interesting thing is - why do you need re-blessing? might that be a XY Problem?

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");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}