Craft Suffixes Cannot be Changed to protect the Suffixes. There is no way to guarantee the T1 Life is not deleted by the Veiled Orb, but there's a 50% chance the Metamod gets removed instead.

In order for a mod to be unveiled, it must be taken to Jun. Once unlocked through Jun, Veiled Modifiers can be added to gear via the Crafting Bench (though it will be a lesser version of the non-benchcrafted variant).

Before unveiling, it's important to block the highest-weight veiled modifier(s) that you don't want. For a Body Armor like this you'd craft (8-9)% Chance to Block Attack Damage.

In Path of Exile, Veiled Crafting refers to crafts which use a Veiled Orb to add Veiled Modifiers to items. These are both apart of the Betrayal League mechanic. This guide assumes you understand the basics of The Immortal Syndicate.

For the example you have a Body Armor with 1 Prefix, +129 to Maximum Life, and 3 Suffixes. The goal is to add a Veiled Prefix mod without losing any of the current mods already on the item.

Veiled Mods are item modifiers unique to the Betrayal league mechanic. Items with Veiled Modifiers can be dropped by Betrayal encounters or added to items with Betrayal-specific crafting (e.g. a Veiled Orb).

If you're lucky, the Veiled Orb removes the Suffixes Cannot be Changed then adds a Veiled mod in its place. Since you already have 3 Suffixes, a Prefix is added. If there were only 2 Suffixes, it would be a 50% chance for either.

A Veiled Orb adds a Veiled Mod. The Orb removes a single modifier at random before adding a Veiled mod. Veiled Orbs are acquired as a drop from the Mastermind encounter from Betrayal.

An ideal unveil would be (9-10)% increased maximum Life, (9-10)% increased maximum Mana or (30-35)% chance to Avoid Elemental Ailments, (30-35)% chance to Avoid being Stunned depending on your build's needs.