Let us suppose that the primacy was transferred from the See of Rome and is now joined to another: Naples, Paris, or Cologne. Then for this imaginary future time it will not be true any longer what was defined, and what had to be held until that time by everyone by the Catholic Faith: "The Roman Pontiff himself is the successor (not only was once the successor) of Blessed Peter the Prince of the Apostles, and the head of the whole Church." And as a result it will no longer be an anathema that "he who says the Roman Pontiff is not the successor of Blessed Peter in the primacy." Nor must anyone say anymore, "The Roman Church, by the decision of Our Lord, holds ordinary power over all others (not only used to have that power)." And this is none other than the power of the jurisdiction of the Roman Pontiff, by which both shepherds and faithful both individually and collectively are bound. We'd also have to change what had been proposed for belief until that time, in the profession of Lyon and Trent: "The holy Roman Church holds the highest and fullest primacy over the entire Catholic Church. I acknowledge the Roman Church as the mother and mistress of all churches, and I promise obedience to the Roman Pontiff the successor of Blessed Peter the Prince of the Apostles and the vicar of Our Lord." In sum, the true Church of Jesus Christ would not be any longer the Roman Catholic Church, but rather the Neapolitan Church, or the Parisian Church. The very absurdity of these consequences, which are intolerable to the ears of Catholics, but which are necessarily contained in the idea of moving the see, demonstrate the unchangeableness of the object that is proposed for belief in the definitions and professions of faith.

Read this excerpt below from the Pike letter to Mazzini in 1871 for more clues as to how the Roman Pontiff is "transported" elsewhere. Of course, this is the view from the perspective of the Freemasons. But it seems to align with other prophecies.

“It is also said that the Pope of superstition, sitting in Rome at the time of the fragmentation, will refuse to acquiesce in the new situation of his Church, and that he will hurl his thunderbolts, henceforth powerless, against the governments participating in this great work of social salvation. Then, he will be abandoned by a multitude of his priests in the various countries, since many will have been won over to us in advance; Italy will expel him, and the accursed Papacy will be wandering and obliged to return for a time into darkness [or obscurity]; for the governments will bring severe penalties against those who would maintain their adherence to it and who would thus conspire with it.

"But it is also written that the Wandering/Straying/Erring Pope [Pape-errant], shepherd of a scattered flock, pilot of the helpless boat of Cephas, and sixth successor of the man of pride under whom the temporal power of the infamous pontificate has collapsed, will be collected, after expulsions upon expulsions, by the Slavic autocrat, who will affect to render him great honors. Adonaism will then attempt to reconstitute itself as before the expulsion from Rome; the Wandering Pope [Pape-errant] being near death in Russia, the imperial autocrat will prostrate himself at his feet, and the nations practicing until then Orthodoxy, that is to say the schismatic religion of the Orient, will rally fairly quickly to the old Roman Catholicism, vomited from Italy. The Wandering Pope [Pape-errant], on his deathbed, will be joyful to see these new followers replace the Westerners recently separated from his Church, and, within the nations which will have carried out the fragmentation of Adonaïsm, he will still have the faithful, these hiding to indulge in the practices of the reprobate superstition; before expiring, he will have maintained the episcopate to the bishops of the Orient schism, and he will have instituted, among them, Greek and Russian cardinals. His successor will be a Slav; the seat of the Adonaïe Papacy will be established in the northern city of Peter, with the reservation of reconquering Rome. But it will be in vain that the imperial autocrat, in the hope of extending his domination, will make himself the crusader of Adonaïsm; his efforts will not succeed, and the Church, once Roman, will remain fragmented in the nations of Western Europe. Thus, Russia will be the last refuge and the last bulwark of Adonaism claiming to be Catholic.

...

"Therefore, when the autocratic empire of Russia has become the citadel of papist Adonaism, we will unleash the nihilist and atheistic revolutionaries, and we will provoke a formidable social cataclysm, which will clearly show to the nations, and in all its horror, the effect of absolute unbelief, the mother of savagery and the bloodiest disorder. Then, everywhere, the citizens, obliged to defend themselves against the mad minority of the rebels, will exterminate these destroyers of civilization; and the countless disillusioned of Adonaism, whose deistic souls will have remained until this moment without a compass, thirsting for an ideal, but not knowing to which god to award their homage, will receive the True Light, by the universal manifestation of the pure Luciferian doctrine, finally made public, a manifestation which will arise from the general movement of reaction, following the crushing of atheism and Adonaism, both at the same time defeated and exterminated.

"The birth of the religion of Lucifer the Good God, establishing itself forever without a rival on the terrestrial globe, could not be an instantaneous operation, nor of a year, nor of five years [lustre], nor of a century. The lasting work is that which is created by slow progression. The 19th century saw the conception of true and good catholicism; the 20th century will be the century of gestation, to surely bring the birth to its term fixed in the book of heaven (September 29, 1996 of the Christian era then ended).

“Written and given in Solemn Vault, and signed, at the feet of the Sacred Palladium, by the Sovereign Pontiff of Universal Fɾҽҽmαsσɳɾყ and by the ten Elders composing the Most Serene Grand College of Emeritus Masons, in the Supreme Orient of Charleston, in the beloved Valley of the Divine Master, on the 29th and last day of the Moon Ab of the year U00871 of the True Light (August 15, 1871, vulgar era). »

This is the secret plan, which formulates and summarizes the tactics and hopes of the sect.

Here is another quote from Cardinal Billot:

• A guarantee of eternal salvation. The Church does not "make" someone a saint. Instead, canonization is an official declaration that a person is certainly in heaven and enjoys the beatific vision. To deny this would imply that the Church can lead the faithful into error, which contradicts the doctrine of papal infallibility when defining matters of faith and morals for the universal Church.
• Theological certainty, not dogma. The infallibility of canonization is considered a matter of theological certainty, not a divinely revealed dogma of faith. This distinction means that while denying it is a grave error and contrary to the universal consensus of theologians, it is not formally heretical.
• Respectful discussion is permitted. While a Catholic is not free to deny the sanctity or heavenly status of a canonized saint, it is permissible to respectfully discuss concerns about the canonization process itself, such as its speed or thoroughness. This is not the same as denying the infallibility of the final judgment"

• The Avignon Papacy: The most direct historical example is the Avignon Papacy from 1309 to 1377, when seven popes resided in Avignon, France. Although controversial, these were considered valid popes, demonstrating that the Pope does not need to live in Rome to exercise his ministry.
• Apostolic Succession: The authority of the papacy is derived from the Bishop of Rome's role as the successor to Saint Peter. While Peter died and was buried in Rome, his successor's ability to lead the Church is not dependent on being physically present in the city.
• Emergency relocation: Popes have made contingency plans for relocating the papacy in dire circuмstances, such as during wartime. This demonstrates the Church's understanding that the institution can physically move if necessary."

Well, the Papacy had been in exile at Avignon for quite some time, and not a few prophecies refer to the Pope having to flee Rome ... 

Now you seem to be asking what the theological level of certitude for that is, without having addressed any of Cardinal Billot's arguments, or addressed why it would be possible to reject the Council of Lyons or the Council of Florence.