The Assignable Learning Activities page in Configuration enables you to remove assign rights from a learning activity. Doing so removes all assign rights from all accounts for that learning activity. To do so:
Go to Configuration.
Click on the Site Settings folder.
Select Licensing & Usage.
Click on the Assignable Learning Activities option; this opens the Assignable Learning Activities page in the main window.The following option is available when a learning activity is shown as being assigned to Groups or Accounts (the Person icon in the Features column). If the learning activity is assigned to the site only, then this option is not available.
Click on the Context menu (three little dots) for the required learning activity.
Select the Remove assign rights option.A warning message appears. It asks you to confirm that you want to remove assign rights from that learning activity.
Click Unassign to confirm or Cancel if you have changed your mind.
After you confirm the change, the system removes assign access from every account that had assign rights to that learning activity. Please note that the learning activity remains assigned to the site and the site administrator can still use the enrol function and give an account assign rights to that course if required.