DiskGenius provides the function to convert primary partition to logical as well as convert logical partition to primary without data loss. One MBR disk may contain 4 primary partitions at most or 3 primary partitions with one extended partition, thus partition converting between primary and logical has some limitations.
Step 1. Right-click the primary partition you want to convert and choose "Convert To Logical".
Step 2. Click "Save All" button on the tool bar and a message box shows up. Click "Yes" to make the converting take effect.
Note: Since logical partition is 63 sectors bigger than primary partition, there should be at least 63 free sectors in front of the primary partition when changing it to logical.
Step 1. Right-click on the logical drive you want to convert and select "Convert To Primary" option from context menu.
Step 2. Click "Save All" from tool bar and click "Yes" from the pop-up window.