Hephaistos' workshop

[Inardesco]

So how do these engravings work exactly on weapons/armour that already have the engraving?

Lets say I have a piece of armour +10% warrior damage and upgrade the engraving to +12% warrior damage.

Will it automatically assign the boost in engraving or do I need to upgrade the armour for it to take hold?

[Perplex]

If you engrave it with +12% warrior damage it will be 10%+12% so a toal of 22%, if the 10% is the base stat on the armor before engravings.
If you already have engraving of 10% and upgrade it to 12% then you need to re-engrave it for the 12% to override the 10%.