How to force Avamar client deactivation/activation from Administrator console

Hi Guys,

We have Avamar 7 for Desktop and Laptop backup, and are facing big problem with clients which become deactivated after OS re-image on these machines or after HW (Laptop or Desktop) replacement (with keeping the same hostname), but in Avamar Administrator Console or in Client Manager it is always showing that these clients are still activated. We would like to reactivate these clients from Administrator Console or in Client Manager instead to do it from client side (we have important number of these clients), I tried it for some machines but it didn't work, any help or tips? Thanks.