If you need to delist a site from being supplied by a supplier follow these steps


Step 1: On the associated sites tab for a supplier, select the site on the Edit menu & at the bottom of the page you can select Delist Supplier à note this is only available if you have Admin permissions 

Step 2: Choose what you want to save or do from the checklistthen select Delist Associated Site

Step 3: The status of the site will revert to delisted