31 The Church's commitment to ecumenical dialogue, as it has clearly appeared since the Council, far from being the responsibility of the Apostolic See alone, is also the duty of individual local or particular Churches. Special commissions for fostering the ecumenical spirit and ecumenical activity have been set up by the Bishops' Conferences and the Synods of the Eastern Catholic Churches. Suitable structures similar to these are operating in individual Dioceses. These initiatives are a sign of the widespread practical commitment of the Catholic Church to apply the Council's guidelines on ecumenism: this is an essential aspect of the ecumenical movement. Dialogue has not only been undertaken; it has become an outright necessity , one of the Church's priorities . As a result, the "methods" of dialogue have been improved, which in turn has helped the spirit of dialogue to grow. In this context mention has to be made in the first place of "dialogue between competent experts from different Churches and Communities. In their meetings, which are organized in a religious spirit, each explains the teaching of his Communion in greater depth and brings out clearly its distinctive features". Moreover, it is useful for all the faithful to be familiar with the method which makes dialogue possible.
Source: Ut Unum Sint (Vatican.va)