Item Rebuilding
Once you have learned the Item Rebuilding skill from the Skill Tree, you will be able to add extra ingredients to completed items and make them even stronger.
Just like synthesis, Item Rebuilding can be performed from the altar inside the atelier or from Simple Altars in building areas.
Performing Item Rebuilding

Select the item you would like to rebuild.
Next, choose ingredients to add to cores or slots that have no ingredients.
Ingredients added previously through synthesis or Item Rebuilding cannot be switched out.
Certain effects and synthesis skills cannot be activated during Item Rebuilding.