If you have some basic competence with woodworking tools and a vice or clamping workbench you can re-handle a Gransfors axe. It takes care and patience and, as always, working with tools can be dangerous. Consider the risks, not least dropping a razor sharp axe head on your foot. If you aren’t competent try asking a friend or a woodworker who is.
My woodwork is fairly rough and ready as you’ll see below, especially the last image which is a ‘how not to do it.’
Now you need to support the head in the jaws of the vice and drive the handle out with a suitable piece of wood and hammer. Don’t let the head fall on your foot!