That kinda works.
If the character has acquired items, or advancements that would not be allowed during creation, for any reason, the validation errors come out in droves, and in the case of those things that were purchased with Karma (spells, skill increases, bonds, etc.) those result in an over spending of BP that prevents you from locking the character again.
I've had to print a hard copy of the affected character before making the needed corrections, deleting all off the advancements, unlock the character, make the necessary changes, delete any items that are flagged as invalid during creation, lock the character, give the flagged items back to the character for FREE, then re-add the advancements.
It's a royal pain for a character with lots of advancements or restricted/forbidden gear.