Legendary armor with selectable stats would address the need for two sets of armor with different stats—but what about the runes? Don’t worry, we have you covered.
When you apply an upgrade (rune or infusion) to a piece of legendary armor and there is already an upgrade in the slot you have selected, the existing upgrade will be moved to your inventory and the new upgrade will replace it. Simple as that. When Flashpoint releases next Tuesday, players will be able to complete the collection and legendary armor will be obtainable (and viewable in the wardrobe). Each piece can be worn individually or as a complete set, so you are free to mix and match.
Read More:
https://www.guildwars2.com/en/news/legendary-armor-is-coming-soon/