Same as would on a guitar i suppose if it has a dovetail neckjoint, using heat and steam to liquify the glue and it should come right out.
I found this on the internet
On guitars with dovetail neck joints, I take out the 15th fret or whichever fret is right over the dovetail joint. The fret should be heated to make removal easy and to avoid fingerboard chip-outs.
If the neck was joined to the body before finishing (which is common with Gibsons, Guilds, and Gibson-made Epiphones, for instance), the finish needs to be carefully cut at the sides of the heel in order to allow the neck to slide free. This is a tricky procedure that makes it much harder to do inconspicuous resets on guitars made this way. Martin, Santa Cruz, and Larrivée guitars, among many others, have their necks glued on after finish, making resets much easier to hide.
The next step is gently heating the part of the fingerboard that’s over the body to soften the glue joint with the top. Applying lemon oil to the fingerboard will help transfer the heat through the board and prevent excessive drying and cracks. The idea here is to preserve the structural integrity of the fingerboard by not having to cut through a fret slot. I then loosen the fingerboard over the body by carefully slipping in a sharpened blade that looks much like a very thin, wide oyster knife. A bit of spray-on dry lubricant makes this step go easier.
Next, two holes are drilled through the fret slot down into the dovetail area. A basketball pump needle attached to a tube and steam source (I use a cappuccino steamer) introduces steam into the dovetail joint. The steam heat softens the glue in the dovetail, allowing the neck to be removed from the guitar’s body.
I recently removed a mandolin neck off a very cheap one that was dove tailed. I pretty much just cut away the finish with a pocket knife and then beat the crap out of it from the bottom with a soft mallet. Hope that helps
I recently removed a mandolin neck and grafted it to a cigar box. I've been told steam is the way to go. My wife has a clothes steamer and I steamed the heel/neck joint well and then tapped and worked it off. It made a decent cigar box mando, but the lower fretboad did warp on me. Good luck to you.
The secret that everybody misses for some reason is denatured alcohol (assuming its assembled with hide glue). If there's thick lacquer coating, you may want to score it first like Mark said. After that, use an eye dropper and the alcohol will creep into the seam and loosen it up for you. Steam (water), while it works great on the glue, you have to be careful with because of the wood.