The Stockton (Calif.) Unified School District has reduced the amount of a planned February bond request from $673 million to $464.5 million. The lower figure requires 55 percent approval; the bigger amount would have needed a two-thirds majority. Among the projects included in the package: $160.6 million to replace K-8 portable classrooms; $133.4 million for play fields, hard courts and swimming pools; $52.8 million to modernize Edison High School and $56.6 million to modernize Franklin High.