There are no Restart Grace Period or Activate/Destroy buttons on the subscription screen in the Termination Queue under
Top > Account Director > Subscription Manager > Subscriptions > Termination queue tab > Some subscription.
They appear only if a subscription is selected manually, without using any search filter and pressing the Search button.
The buttons disappear only after a search is done.
Such behaviour was classified as the software issue PBAS-30174 and was fixed in OBAS 4.5.6
To resolve the issue, please upgrade to 4.5.6 as described in How to upgrade OBAS system to the latest available version.
As a workaround for older OBAS versions, please locate the subscription in the Termination Queue and click on it without applying any search filters. In other words, to see the buttons one must visit subscriptions pages directly, without searching for them.