Go into Administration > Libraries & Sets > Suppliers > Contacts > Global. Click on ‘Download Live Data’. This will export all global contacts into an excel sheet. For the contacts you wish to expire from BC-3, remove them from the excel. Add in the contacts you wish to import, leaving the ‘Id’ and ‘Contact Id’ blank as these are system-generated. Go back into BC-3, Administration > Libraries & Sets > Suppliers > Contacts > Global and search for your saved file. Import.
You can view your import status by going into Reports > System Audit > Imports after giving it ample time to process your import (usually 30 minutes).