Tens of thousands of Chicago Public Schools educators mourned the death of former Chicago Teachers Union President Karen Lewis on Monday as they faced a critical choice over whether to accept a plan to gradually return to in-person learning beginning this week.

When the day was over, the union’s house of delegates voted overwhelmingly to endorse a reopening agreement with the school district, kicking the final decision to a full vote by the union’s approximately 25,000 members. About 85 percent of delegates voted in favor at a Monday night meeting, according to a union official.