You can stop sharing an item, see who it's shared with, or change the permissions others have to it, if you're the owner of the item.
Note: You can't change the permission of a sharing link from edit to view or from view to edit. The way around it is to delete your sharing link and create a new one with a different permission.
Files and folders can be shared by sending someone a sharing link, or by giving them direct access to the file or folder. (People may also have access to a file or folder if they've been given access to the site itself.)
If you are the file owner, you can stop sharing the file or folder.
If someone has been given direct access, or has access through a specific people link, you can also change the sharing permissions between view and edit.
Here are the steps:
1.Select the file or folder you want to stop sharing
2. Right click the item you wish to manage permissions on and select the Share option
3. At the bottom of the sharing window is the existing sharing permissions for any people you have granted access to or links. Select the one you wish to modify (hover over each to view details)
4. On the manage access window you can disable any shared links you have created or revoke access for specific users. Click the X for any that you wish to revoke access to specifically and when finished close the window.