I have created a custom list named “K2 Workflow Tutorials” in which K2 workflow will be created to stop inheriting list permissions.
Go to K2 designer, drag and drop Stop Inheriting List Permissions step from the Lists workflow steps in the ribbon interface.
Figure 1: Stop Inheriting
Specify a site collection and then click on Next button.
Figure 2: Click next
Specify filters for the list to update and then click on Finish button.
Figure 3: Finish Button
Deploy the workflow. Create a list item with title field value as “Test”. After few minutes the workflow will be completed and it will stop inheriting list permissions for the list having title as “Test”.