Hopefully, the handle will have been glued with a protein hide glue, if at all. Such glues are reversible with heat ( 140° F – 60°C or so) and some moisture. Hot ( not too hot, it kills the glue) water and a heat gun is usually enough.
Sometimes you get lucky and just a piston fit was used.
In that case, just a steady upward pull will work.
And when you reglue, use hide glue again .