Hi All,
Please don't be confused on the above information. There is no way which can downgrade Windows 2008R2 ENT to 2008R2 STD edition. The above discussed "Downgrade Kit" can be used for acquiring licensing rights
for downgrading an OS. So, whatever may be the licensing model, you have to do the fresh install to downgrade the OS version.
For more information on the downgrading rights, please refer the below links.
http://www.microsoft.com/oem/en/licensing/sblicensing/Pages/what_to_do_downgrade_rights.aspx#fbid=eocm99qIpEs
http://www.microsoft.com/oem/en/licensing/sblicensing/pages/downgrade_rights.aspx#fbid=eocm99qIpEs
You can run the below command on your server to know the list of target OS SKU's where you can move.
"DISM /Online /Get-targeteditions"
Thanks,
Vaibhav Dixit