Yes. Here are the steps to remove ALL employees assigned to a single tool #:

BE CAREFUL!  This procedure does not have a special confirmation and cannot be undone! 
  1. Launch Tool #327 CU*BASE Employee Security
  2. Click the All Tool Assignments button
  3. HINT: If you wish, click the Print button and generate a copy of the Assigned Tools Audit Report for the tool before proceeding, to help recreate the assignments should something go wrong.
  4. Select the tool in the list - notice the # of employees already assigned to this tool in the far-right column 
  5. Choose the Assign to Employee option
  6. A list of all employee IDs will appear; each ID assigned to this tool will be highlighted
  7. Click the Unselect All button (or you can hold the CTRL key and click on each of the highlighted IDs you wish to de-select)
  8. Use Enter or click the right arrow button to save the changes
  9. Notice that the number of employees shown in the right-right column of the Assign Tools to Employees screen will have changed