Student studentToDelete;

//1. Get student from DB

using (var ctx = new SchoolDBEntities())

{

    studentToDelete = ctx.Students.Where(s => s.StudentName == "Student1").FirstOrDefault<Student>();

}

//Create new context for disconnected scenario

using (var newContext = new SchoolDBEntities())

{

    newContext.Entry(studentToDelete).State = System.Data.Entity.EntityState.Deleted;    

    newContext.SaveChanges();

}