What kind of ferrule? I assume unibut, or similar. I have done this to a trolling set to change UB sizes before they made adapters.
Easy
Do not use heat. Temps required to loosen the epoxy will destroy the blank.
Carefully cut the ferrule off.
Cut the base off first with a hack saw. Now you have a sleeve. Next. use a bench grinder with a new stone with a sharp edge. Grind down a line until you get a thin linear cut. Now you can pry open the ferrule and remove it. Your bad glue job will make this part easier.
Use a sharp chisel and work it under and around the ferrule