Database: insurance_fnol
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"