If Pope Benedict XVI were at this moment assumed into heaven and by some unusual turn of events I found myself taking his place, I would seriously consider making a proclamation along the following lines:
Most respected fellow disciples of Christ under the guidance of the divinely esteemed Church of Rome:
Sacred Scripture and Sacred Tradition inform us of the gravely sinful and harmful nature of schism. This most humble pope of Rome are painfully aware of this fact on account of the numerous divisions among the Apostolic Churches which arose in and around the years 424, 451, and 1054. I have come to see that, in order for the two lungs of the Church–the Catholic and Eastern Orthodox Churches–to be reunited, we will have to reexamine a few points, for the Lord prayed for us to be one as he and the Father are one, and the will of God must always trump the whims of man.
By my supreme authority as the successor of St. Peter the Apostle in his most splendid chair, and the chief shepherd of the Church, and the most humble Vicar of Christ on Earth, I declare, define, say, and proclaim that the doctrines of the filioque, papal universal jurisdiction, and papal infallibility are no longer to be considered articles of Catholic faith. By the selfsame authority, I pledge that no more ex cathedra statements will proceed from the Apostolic See other than those necessary to remove all obstacles which stand solidly and unmovingly in the way of the reunion of the ancient Churches. Moreover, I bind firmly all my successors in the name of Jesus Christ to this promise which I have solemnly made.
May Our Lord Jesus Christ bless you and protect you and keep you in all ways comprehended most deeply by the omniscient mind of God, and may Our Lady the Blessed Virgin Mary pray unceasingly for your welfare and salvation now and until the hour of your departure into the next world. Amen.
Thank you.
It isn’t that easy… which is the problem. The hypothetical encyclical above is a pipe dream.
If someone has thought of a silver-bullet solution to end the Great Schism between East and West, the Latin Catholics and Eastern Orthodox would have come into full communion with each other by now.