using System.Data.Entity; using System.Linq; var db = new MyDatabaseContext(); var existingUser = db.Users.First(u => u.Id == 1); existingUser.Name = "John Smith"; db.Users.Attach(existingUser); db.Entry(existingUser).State = EntityState.Modified; db.SaveChanges();In this example, we are querying the database for a user with Id == 1, modifying their Name property, and then attaching the entity to the context. Finally, we set the entity's state to EntityState.Modified and save changes to the database. The package library used in this example is likely Entity Framework, which is a popular object-relational mapping (ORM) tool for .NET applications.