These neck heels are glued into a pocket by hide glue alone, with no tenon or dovetail joint to help hold it, just like a violin. Getting these necks out is a very different from say, a Martin neck. If you don't know how to soften the glue quickly, things can go wrong. Many luthiers have their own take on it. Some guys use heat lamps, others drill holes in the fret slots to shoot in steam, and some just don't want to do the work due to a lack of info about how it's done. I've seen many messed up Hofner basses from people who just went too far and forced things, using to much heat, not enough moisture, thus damaging finishes, bindings and joints.
Heat alone won't soften hide glue...you need moisture too! This is why heat guns and heat lamps alone are a mistake...in addition, they can soften and even melt bindings and lacquer.
I've only done a few Hofner resets, but I researched things carefully, spoke to Hofner directly, and a few luthier's I trust. Hofner told me to simply keep pouring hot water all over the joint until it came apart...Man, I don't know about that! The joint was pretty tight, and it would take hours of doing that to soften the glue enough to pull the neck out! All that water can't be good for the wood and glue seams in the body. Bottom line; I spent some time thinking about this, and came up with the best way for ME to do the job of removing the neck in a manner I felt was safe and responsible.
It involved isolating the moisture and heat from the rest of the bass, and zapping the hide glue in as complete and direct a pattern as possible to get the neck out quickly.
I scored along the neck joint with a scalpel to cut a nearly invisible line in the finish where the neck heel joins the body, binding and heelcap. This way the lacquer won't craze or chip as the neck is removed, and it allows the hot water and steam to get into and around the joint more completely.
I then I carefully removed the heel cap, and made three tiny holes about an inch long along the body binding/heel cap line just above the the neck heel itself. (The photos are pretty clear) The long steaming needle can easily slide all the way into the joint along the bottom of the pocket on both edges and the center this way. A few minutes of steam in each position was all it took to melt the glue away, and the neck pulled easily out of the pocket. When I reglue the neck at the correct angle, the heel cap will go back on, and cover the three little holes completely. The reset will be nearly invisible, and structurally sound. You'll notice there is no damage to the finish, binding or body here. Once you get at hide glue, it softens fast. The trick is to get the steam and hot water right to the glue directly to keep the process short and sweet. This neck was out in five minutes.
You can see my little Italian made 1/4" mini ball valve in-line on the steam hose. This allows me to regulate the steam pressure and heat to avoid clouding the finish, damaging the binding, and delaminating the wood glue-ups in the neck.