If you are not satisfied with the stats of your Ultra Mecha, you can go to the Shop to purchase the Ultra Mecha Retrogression item, which can retrogress your Ultra Mecha to common quality. All evolution stats will becleared, allowing you to evolve the Ultra Mecha again and re-choose evolution stats. Please note that after using the Retrogression item, the Mecha's evolution buff will be cleared and you need to re-evolve the Mecha. Please think twice before using the item.