To find the concurrent manager for a specific concurrent request.

SELECT b.user_concurrent_queue_name
FROM fnd_concurrent_processes a,
fnd_concurrent_queues_vl b,
fnd_concurrent_requests c
WHERE a.concurrent_queue_id = b.concurrent_queue_id
AND a.concurrent_process_id = c.controlling_manager
AND c.request_id = :p_request_id