Question: Which customers have used both the service named "Close a policy" and the service named "Upgrade a policy"? Give me the customer names.
SQL: 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" INTERSECT 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  =  "New policy application"