82 It is understandable how the seriousness of the commitment to ecumenism presents a deep challenge to the Catholic faithful. The Spirit calls them to make a serious examination of conscience. The Catholic Church must enter into what might be called a "dialogue of conversion", which constitutes the spiritual foundation of ecumenical dialogue. In this dialogue, which takes place before God, each individual must recognize his own faults, confess his sins and place himself in the hands of the One who is our Intercessor before the Father, Jesus Christ. Certainly, in this attitude of conversion to the will of the Father and, at the same time, of repentance and absolute trust in the reconciling power of the truth which is Christ, we will find the strength needed to bring to a successful conclusion the long and arduous pilgrimage of ecumenism. The "dialogue of conversion" with the Father on the part of each Community, with the full acceptance of all that it demands, is the basis of fraternal relations which will be something more than a mere cordial understanding or external sociability. The bonds of fraternal koinonia must be forged before God and in Christ Jesus. Only the act of placing ourselves before God can offer a solid basis for that conversion of individual Christians and for that constant reform of the Church, insofar as she is also a human and earthly institution, which represent the preconditions for all ecumenical commitment. One of the first steps in ecumenical dialogue is the effort to draw the Christian Communities into this completely interior spiritual space in which Christ, by the power of the Spirit, leads them all, without exception, to examine themselves before the Father and to ask themselves whether they have been faithful to his plan for the Church.
Source: Ut Unum Sint (Vatican.va)