I don't understand the idea of resigning from papacy. I know that according to RCC papacy is a office and not a sacrament but still there is something fishy in the idea.
Same here. A Pope voluntarily abdicating doesn't have much of a precedent if you discount the Pope whom Dante saw in hell.
"Historical evidence for papal resignations is limited
, especially if one eliminates resignations that may have been forced.
Clement I (92?-101): Epiphanius asserted that Clement gave up the pontificate to Linus for the sake of peace and became pope again after the death of Cletus.
Pontian (230-235): Allegedly resigned after being exiled to the mines of Sardinia during persecution of Maximinus Thrax.
Cyriacus: A fictional character created in the Middle Ages who supposedly received a heavenly command to resign.
Marcellinus (296-304): Abdicated or was deposed after complying with Diocletian's order to offer sacrifice to pagan gods.
Martin I (649-655): Exiled by Emperor Constans II to Crimea. Before he died, clergy of Rome elected a successor whom he appears to have approved.
Benedict V (964): After one month in office, he accepted deposition by Emperor Otto I.
Benedict IX (1032-45): Benedict resigned after selling the papacy to his godfather Gregory VI.
Gregory VI (1045-46): Deposed for simony by Henry III.
Celestine V (1294): A hermit, elected at age of 80 and overwhelmed by the office, resigned. He was imprisoned by his successor.
Gregory XII (1406-15): Resigned at request of Council of Constance to help end the Great Western Schism."
Perhaps Benedict XVI resigned to help end the Great Schism. Well, I can hope, can't I?