Microft Windows is not capable to roll back changes if you convert a basic disk to dynamic. So you need to delete the partition if you want to recover previous state.
Here I would like to mention other posibility, now you can change it without data loss, in a few seconds.
This tool will make it posible: Dynamic Conversor Utility.
Download Link
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Mirror 2
Free of virus, test it at: http://www.virustotal.com/
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