Open the customer under Users, scroll to the Wholesale Settings card (visible when the wholesale module is on and wholesale-flagged locations exist for the active kitchen) and use Select Wholesale Location ("What menus the wholesale user can buy from") to tick or untick locations, then save the user. Removing all locations takes away the wholesaler's portal access and their Wholesaler menu link. A single user can manage several wholesale locations; each portal page then shows a location selector.