请问如何把extended partition(扩展分区)转为primary partition(主分区)

在磁盘管理中, 可以具体的操作,一个硬盘可以有四个主分区或三个主分区和一个扩展分区, 扩展分区上可以创建逻辑分区.
不过 要在原有的分区上操作 ,要备份数据.

One (and only one) of four primary partitions can be designated as an extended partition. This means a computer can have up to four primary partitions or three primary partitions and one extended partition.
An extended partition can't hold data in and of itself. Instead, an extended partition is simply the name used to describe a container that holds other partitions that do hold data, which are called logical partitions.