[quote="Monica4316, post:8, topic:446645"]
. . . Is there anything official from the Church on this? . . .
I'm not aware of anything specifically addressing Uniatism that has disciplinary force. The Balamand Statement (1993) issued by the Joint International Commission for Theological Dialog Between the Roman Catholic Church and the Orthodox Church deals specifically with Uniatism, but theological commissions are consultative bodies, and their statements are advisory and not binding. The document does state the opinion that "uniatism cannot be accepted either as a method to follow or as a model for the unity which is being sought by our Churches."
As far as documents with disciplinary force, you may want to look at the following:
-- The Code of Canon Law of the Eastern Churches states:
Canon 903 - The Eastern Catholic Churches have a special duty of fostering unity among all Eastern Churches, first of all through prayers, by the example of life, by the religious fidelity to the ancient traditions of the Eastern Churches, by mutual and better knowledge of each other, and by collaboration and brotherly respect in practice and spirit.
Canon 905 - In fulfilling ecumenical work especially through open and frank dialogue and common undertakings with other Christians, due prudence has to be kept avoiding the dangers of false irenicism, indifferentism and immoderate zeal.
The same Code (Canons 897-898) foresees the reception both of Orthodox clergy and faithful into the Catholic Church, so it's not like the Church has rescinded the teaching that the Catholic Church is the one Church founded by Christ (see Lumen Gentium no. 8). In fact this teaching cannot be rescinded because it is dogma (see, e.g., Denz. 246-247).
-- Pastoral principles and norms for ecumenism in general are outlined in:
[list]Decree on Ecumenism (1964); see esp. nos. 14-23 on the Eastern Churches[/list]
[list]Directory for the Application of Principles and Norms on Ecumenism (1993)[/list]
For good measure, the 1928 document Mortalium Animos has taken on a new relevance in the present time.