If he tried this, the rest of the EO churches would hold a synod and excommunicate him and then go back to keeping the faith unchanged like the previous 2,000 years.
It's the benefit of having a decentralized structure. If bishops decide to fall into heresy and join Rome, it doesn't affect Orthodoxy as a whole.
Roman Catholics have a system that relies on 1 guy in Rome being perfect for the rest of eternity. Otherwise, their system falls.