Well, let’s see. As a “symbolic gesture”? the excommunication against the Patriarch of Constantinople Michael Cerularius was lifted by the RCC about one thousand years after it was put into effect. (I guess it was a mutual lifting). And during this time the schism hardened to the point where some Orthodox say that the Sacraments (including Baptism) of the RCC are invalid. So the Vatican could wait another one thousand years, and after that thousand years has passed, and after the position of those in the SSPX had hardened, it could then lift the excommunication of Archbishop Lefebvre as a symbolic gesture. Another alternative would be not to wait, but to try to heal the schism at this time and to make the symbolic gesture of lifitng the excommunications now and to make every effort to work together in a spirit of charity and understanding.