optDesign -postRoute in PAC flow

Hi,

I want to optDesign in Post Assembly Closure Flow in soc Encounter. But it is a limited access feature. I get the following error when i attempt it. 

**ERROR: (ENCSE-24): 'optDesign -postRoute in PAC flow' uses a limited access feature that requires special setup before you can use it. Please contact Cadence support for more information on how to access this feature.

How can I enable this feature.

Best regards,

Ahsen