How do Seventh Day Adventists understand "a form of [a] God" in Philippians 2:6?

SDA is Trinitarian and believe that Jesus in his preexistence was Michael the archangel. Do they then believe that Jesus' preexistent form was that of an angel all the time or that Michael was a form he adopted when doing messenger work and such? In other words is Jesus an angel reincarnated as a man or some other "divine form" incarnated as a man? And what do they say going on with Michael waging war in heaven post-resurrection?