The item must contain at least a 6th bonus in order to change. It is advisable to have the 7th bonus on the item aswell before changing to prevent loss of resources.
When you use it on an item, there is a chance the change is applied and there is no option to return to the previous bonuses.
Use Orison to guarantee a change each time you use it.
The change is only applied on the 6th and 7th bonus. The 1-5 bonuses are untouched.
