EA's Jeremy Dalberg has published a 128th "Five on Friday" Q&A feature to the official Ultima Online website.
Skill Jewelry and Form-Changing Spells in Publish 56
I didn't have a version of the question handy, but this has come up a number of times. Currently, if you use skill jewelry to increase your skill, cast a form-changing spell (such as Necromancy's Vampiric Embrace) then remove the skill jewelry, you remain in that form.
This will be changing in Publish 56. What will happen is if you lower your skill past the threshhold to be able to cast that particular form-changing spell, (whether by removing items, using a soulstone, or even using the Test Center set skill command) you will revert to your normal form. This will affect not only the various forms available with Necromancy but Magery (Polymorph,) Ninjitsu (Animal Form,) and Spellweaving (Reaper Form.)