There is none. At one time there was an official Orthodox/PNCC Commission but it was dissolved. Not sure why. I suspect the PNCC had no desire to renounce their post-1054 but pre-Vatican I past, even while they reject the Western Councils after the Seven, IC, Papal Infallibility, Purgatory, etc. They also have practices Orthodox don't approve of: married bishops, marriage after ordination, general absolution for adults without private confession, Sacred Heart devotion etc. Also a large number of their priests are former RCC priests whose only problem with the RCC is their not allowing married priests, so probably not a big voice for unity with the Orthodox there. I think one of their parishes did leave and join the AWRV. St Augustine's in Denver?