Deactivate a Single Client in Policy

Hello Experts,

We are using windows server 2008 with 7.6.0.1 master server. We have some clinet failing as these have been shut down manually in policy. These are in different diferent policies. I dont want to delete it.

So pls let me know how to deactivate a single client for time being than i will reactivate it. The option is greyed out but i believe there must be an option for this as its a basic requirement.

Thanks,