SELECT t1.customer_name FROM customers AS t1 JOIN first_notification_of_loss AS t2 ON t1.customer_id  =  t2.customer_id JOIN services AS t3 ON t2.service_id  =  t3.service_id WHERE t3.service_name  =  "Close a policy" OR t3.service_name  =  "Upgrade a policy"
Find the names of customers who have used either the service "Close a policy" or the service "Upgrade a policy".
[Schema (values) (types)]: | insurance_fnol |  Customers : customer_id (text) , customer_name (number) | Services : service_id (text) , service_name (number) | Available_Policies : policy_id (text) , policy_type_code (number) , customer_phone (text) | Customers_Policies : customer_id (text) , policy_id (number) , date_opened (text) , date_closed (number) | First_Notification_of_Loss : fnol_id (text) , customer_id (number) , policy_id (text) , service_id (number) | Claims : claim_id (text) , fnol_id (number) , effective_date (text) | Settlements : settlement_id (text) , claim_id (number) , effective_date (text) , settlement_amount (number);