Can you upgrade armour from breastplate to halfplate?


Agar the Ranger is wearing a Breastplate of Psychic Resistance(DMG, 152), he wants to upgrade his amour to half plate while retaining the magical resistance.

Half plate consists of shaped metal plates that cover most of the wearers body” PHB. 145

Presumably half plate would include a breastplate; RAW can Agar wear half plate armour and retain the magical properties of the original breastplate?