Question: Why did Roncalli leave the place where Francesco Fontebasso resided when he died?

Knowledge 1: Francesco Fontebasso
Francesco Fontebasso (4 October 1707 – 31 May 1769) was an Italian painter of the late-Baroque or Rococo period of Venice. He first apprenticed with Sebastiano Ricci, but was strongly influenced by his contemporary, Giovanni Battista Tiepolo. In 1761, Fontebasso visited Saint Petersburg and produced ceiling paintings and decorations for the Winter Palace. Fontebasso returned to Venice in 1768. He helped decorate a chapel in San Francesco della Vigna. [SEP] Knowledge 2: Pope John XXIII
Following the death of Pope Pius XII on 9 October 1958, Roncalli watched the live funeral on his last full day in Venice on 11 October. His journal was specifically concerned with the funeral and the abused state of the late pontiff's corpse. Roncalli left Venice for the conclave in Rome well aware that he was papabile,[b] and after eleven ballots, was elected to succeed the late Pius XII, so it came as no surprise to him, though he had arrived at the Vatican with a return train ticket to Venice.[citation needed]
Knowledge 1: Francesco Fontebasso
Francesco Fontebasso (4 October 1707 – 31 May 1769) was an Italian painter of the late-Baroque or Rococo period of Venice. He first apprenticed with Sebastiano Ricci, but was strongly influenced by his contemporary, Giovanni Battista Tiepolo. In 1761, Fontebasso visited Saint Petersburg and produced ceiling paintings and decorations for the Winter Palace. Fontebasso returned to Venice in 1768. He helped decorate a chapel in San Francesco della Vigna. [SEP] Knowledge 2: Pope John XXIII
On 12 January 1953, he was appointed Patriarch of Venice and, accordingly, raised to the rank of Cardinal-Priest of Santa Prisca by Pope Pius XII. Roncalli left France for Venice on 23 February 1953 stopping briefly in Milan and then to Rome. On 15 March 1953, he took possession of his new diocese in Venice. As a sign of his esteem, the President of France, Vincent Auriol, claimed the ancient privilege possessed by French monarchs and bestowed the red biretta on Roncalli at a ceremony in the Élysée Palace. It was around this time that he, with the aid of Monsignor Bruno Heim, formed his coat of arms with a lion of Saint Mark on a white ground. Auriol also awarded Roncalli three months later with the award of Commander of the Legion of Honour.
Knowledge 1: Francesco Fontebasso
Francesco Fontebasso (4 October 1707 – 31 May 1769) was an Italian painter of the late-Baroque or Rococo period of Venice. He first apprenticed with Sebastiano Ricci, but was strongly influenced by his contemporary, Giovanni Battista Tiepolo. In 1761, Fontebasso visited Saint Petersburg and produced ceiling paintings and decorations for the Winter Palace. Fontebasso returned to Venice in 1768. He helped decorate a chapel in San Francesco della Vigna. [SEP] Knowledge 2: Pope John XXIII
His sister Ancilla would soon be diagnosed with stomach cancer in the early 1950s. Roncalli's last letter to her was dated on 8 November 1953 where he promised to visit her within the next week. He could not keep that promise, as Ancilla died on 11 November 1953 at the time when he was consecrating a new church in Venice. He attended her funeral back in his hometown. In his will around this time, he mentioned that he wished to be buried in the crypt of Saint Mark's in Venice with some of his predecessors rather than with the family in Sotto il Monte.

Answer: for the conclave in Rome