Write SQL query to solve given problem: State the full name of clients with server time of 20 minutes and above.. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT T1.first, T1.middle, T1.last FROM client AS T1 INNER JOIN callcenterlogs AS T2 ON T1.client_id = T2.`rand client` WHERE strftime('%M', T2.ser_time) > '20'