Database: insurance_fnol_minus_1_0
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_first_notification_of_loss as t1 join services as t2 on t1.service_id = t2.service_id where t2.service_name = 'close a policy' intersect select t1.customer_name from customers_first_notification_of_loss as t1 join services as t2 on t1.service_id = t2.service_id where t2.service_name = 'new policy application'