A few points of clarification related to several recent posts; too tired to look for the corroboration, but I know the following to be generally factual. (It may appear that I'm on both sides of the issue, which to a large extent, I am. Bottom line being, whether for or against a calendar change, Orthodox tradition calls for conciliar action and consensus. Due to communications problems and political realities during the 1920's, the traditional process was aborted, and 87 years later, "Some feast, while others fast," within our One Holy Church.)
A significant problem with the implementation of the "Revised Julian Calendar" is that it wasn't a conciliar decision. Constantinople, the convener of the Pan-Orthodox Congress of 1923, was the only Ancient Patriarchate therein represented. There was some consultation with Jerusalem during the conference, which indicated that it could not switch calendars due to the arrangements with the other denominations in regard to use of the shrines. The Church of Russia does not seem to be represented (while the civil war raged, and the Church was so subject to suppression and the persecution of the Bolshevik Communists), although the former Archbishop of the Church of Russia's North American Archdiocese, Alexandr, participated, it doesn't seem he was authorized to represent the Patriarchate of Moscow, though he somewhat acted as if he was so authorized, and was treated as such. Archbishop Anastasi, of the ROCOR attended (perhaps it was Metropolitan Antony, I can't recall for sure), but left during the conference. His reason for leaving isn't documented (to my knowledge), but supporters of the separated Old Calendarists (Traditionalists, Resisters) indicate it was due to the innovations being proposed. Besides Constantinople, the Churches of Serbia, Romania, Greece, and Cyprus were represented.
The Congress did not believe itself to have the competence to implement any of its recommended changes. It expected either the respective first hierarch or the synods of each of the Holy Orthodox Churches would vote upon the recommendations.
Separated Julian Calendarist supporters claim that a popular upraising of the faithful prompted Patriarch Meletios' resignation from the Ecumenical Throne, but it was Turkey's demand for his resignation at the negotiations of the Treaty of Lausanne, with the contingency that without it, they would continue to demand the removal of the Patriarchate from Turkey, that effected his resignation. Venizelos himself was therefore forced to agree to this demand and pressured +Meletios to resign.
+Meletios was forced to leave Jerusalem, while he was a priest (or perhaps a deacon). He was elected and enthroned Bishop of Kition, in the Church of Cyprus. He was later elected Metropolitan of Athens and Archbishop of Greece after Metropolitan Theoklitos was deposed, upon the election of Venizelos as Prime Minister of Greece. Later, when the Royalists regained power, in 1920 (+/-), he moved to America, in exile. He convened the 1st Clergy-Laity Congress of the Greek Orthodox Archdiocese of America in September, 1921, in a move toward securing the recognition of the Ecumenical Patriarchate, due to the disputes with the Church of Greece. In November, 1921, he was elected Ecumenical Patriarch. The traditionalists provide evidence of this election having been faulty, but he was enthroned. He soon after initiated the rescission of the "Tomos of 1908" that had authorized the Church of Greece to serve the Greeks abroad, who were not organized ecclesiastically, and then established the Greek Orthodox Archdiocese of (N&S) America under the Patriarchate (1922). The Church of Greece had initiated disciplinary proceedings against him, prior to his being elected to the Ecumenical Throne; it was pressured to rescind its action after his Patriarchal election. After his resignation, he retired first to Mt. Athos, then to a suburb of Athens. In 1926 (+/-), he was elected Patriarch of Alexandria, with the assistance of the British government. He may have indicated a desire to be considered for election to the Throne of Jerusalem, but nothing came of that initiative. He reposed while serving the Alexandrian Throne and is buried in Alexandria. Separated Julian Calendar supporters assert that on his death bed, while ailing, he exclaimed, "I am suffering because I divided the Church."
While he was Ecumenical Patriarch, the Church of Constantinople did not change calendars. It does seem that he sent the recommendations of the Pan-Orthodox Congress to the Holy Orthodox Churches, seeking their comments.
On March 1, 1923, the government of Greece converted its civil calendar to the Gregorian, in order to be in line with the West, to which it was aligning. But it found that the Greek nation was too accustomed to celebrating Greek Independence Day concurrent with the Feast of the Annunciation, as it had in 1821, the year the revolution was declared. The government put extraordinary pressure upon Chrysostomos, the Archbishop of Athens, who in turn pressured the Patriarchate to make the change; the Church's financial dependence on the state, being a major factor in this matter. +Chrysostomos had participated in a commission that assessed the calendar situation in 1919. The commission reported the need for a pan-Orthodox consensus on this matter, especially the agreement of the Ecumenical Throne. Ecumenical Patriarch Gregory VII, successor to +Meletios, consented to the pressure of the Church of Greece, and Archbishop Chrysostomos implemented the calendar change on March 10, 1924. It was essentially, the government of Greece which forced this conversion, without pan-Orthodox consensus. The Church of Romania accepted the change soon after; in 1926 (+/-), with +Meletios on the Alexandrian Throne, the Patriarchate of Alexandria made the change---it was in the mid-1940's that the Patriarchate of Antioch changed calendars; and the Church of Bulgaria changed in 1968.