Here are some pictures showing how I perform the bolt conversion.
Before you begin you will want to take measurements of the current state and where you want to end up. If you are an experienced tech/luthier you would approach this part the same as a standard reset.
Note where a straight edge laid across the fingerboard meets the bridge. Ideally it should align with the top of the bridge. If your guitar needs a reset it will probably align much lower. Note this both with the guitar tuned to pitch as well as with the strings loosened. This tells you how much the body flexes under string tension.
There are various formulas to determine how much material to shave off of the heel to get the correct neck angle. I'm not going to get into that. Here are a couple of links if you don't know how to do that.
http://fingerlakesguitarrepair.com/taylor-neck-reset/
https://www.liutaiomottola.com/formulae/Reset.htm
The first step of removing the neck is to separate the part of the fingerboard that is over the guitar body. Normally a heat blanket is used to soften the glue. A cloths iron can work or a heat lamp. If you use something like this make sure you protect the top of the guitar from the heat.
If the guitar has a laminate top, heat may soften the glue holding the laminates together, causing layers of the top to pull off. Sometimes the fingerboard can be separated using a good knife without heat.
The next step to cut off the neck as pictured below. I tape thin pieces of metal close to the neck heel so not to mar the body. I use a Japanese pull saw because it makes a very thin, precise cut. It helps to clamp the guitar solidly to you work bench. The truss rod may pass through your cutting path, so the last little bit of wood immediately around the truss rod might not be able to be sawn, and you'll have to break it away and glue it back into the dovetail joint area.
After cleaning up the area and making any repairs you're ready to remove material from the back of the heel to get the correct neck angle. You are only taking out a thin sliver or pie slice, the widest at the bottom, tapering to none at the top (by the fingerboard). I leave the final removal/fitting until I have the bolts in place.
Next drill the holes in the neck heel for the inserts and the neck block for the bolts to pass through. I use 10-24 thread allen bolts either 1-1/4” or 1-1/2”. These and the brass inserts I get from Ace Hardware. I made a drilling template that I use on both the neck heel and block to get proper placement and angle of the holes. I use a 1/4” bit for both.
The brass inserts have notches so you can screw them in using a flat screwdriver. However, brass is very brittle, and if you are screwing into hard wood it's easy to break them. I made this “tap” by cutting notches in the thread and locking two inserts together on a bolt. The notches cut the threads into the wood nicely. I will harden the wood by soaking superglue and recutting with the tap before screwing in the actual inserts. Make sure you let the superglue completely harden before attempting to screw anything in or you'll get part way in and get stuck there.
At this point you're down to final fitting. Unless you're a lot better at this than I, or just lucky, you'll be putting the neck on, tightening the bolts, measuring, checking, removing, sanding, rechecking... a dozen or more times. This is where your under tension vs no tension measurement you took at the beginning comes into play. You may need to put a shim under the fingerboard so you don't get too much drop-off. Then it's just filling in any cracks and cleanup...
