Users with Admin rights, Training Managers or Managers with the Assign Training permission enabled, can unassign curricula from the users under their org structure.
To do so open the main navigation menu and select Curricula under Training.
Find the Course in question and hit on the "arrow" symbol. From the available options select Unassign Curriculum.
Now, you need to select the users you wish to be unassigned. You can either select one by one the desired users from the main list or you can select individual users by filtering the users populating to those being associated with the desired org structure set by you.
Select the desired users, click on the Unassign Employees and the unassignment process will start!