Step 1:  Click on the 'Viewers' icon for the desired file.


Step 2:  Locate the desired user and click the teal 'Lock' icon listed under 'Permissions.' 


Note:  The 'Lock' icon turns from gray to teal when the lock is triggered.


Step 3:  Select 'Reset Lock' from the dropdown menu.


Note: If the user has not triggered the lock, the 'Lock' icon will remain gray and the 'Reset Lock' option will not appear.


Step 4:  Once the lock is reset, a confirmation will appear and the 'Lock' icon will turn back to gray.