Around the country, some communities have canceled 9/11 commemorations because of the pandemic, while others are going ahead, sometimes with modifications. The New York memorial is changing one of its ceremony’s central traditions: having relatives read the names of the dead, often adding poignant tributes. Thousands of family members are still invited. But they’ll hear a recording of the names from speakers spread around the vast plaza, a plan that memorial leaders felt would avoid close contact at a stage but still allow families to remember their loved ones at the place where they died.