By Dan Williams, Nidal al-Mughrabi and Arafat Barbakh JERUSALEM/CAIRO/GAZA (Reuters) – Israel pulled tanks out of some Gaza City districts on Monday, residents said, as it announced plans to shift tactics and cut back on troop numbers, but fighting raged elsewhere in the Palestinian enclave along with intense bombardment. Israel says the war in Gaza, which has reduced much of the territory to rubble, killing thousands and plunging its 2.3 million people into a humanitarian disaster, has many months to go. But it also signaled a new phase in its offensive, with an official saying on Monday the …