What was found
(CAN) CABIN CAUTION AT 19000. CABIN KEPT ON CLIMBING, WHILE WE DESCENDED. CABIN WARNING CAME ON AT 10000 CABIN PRESSURE. DESCENDED TO 10000, CABIN PRESSURE SLOWLY DESCENDED AND WARNING MESSAGE WENT AWAY. HAD TO FLY SLOWLY TO ALLOW PRESSURE TO DROP BEFORE LANDING. CORRECTIVE ACTION: REMOVED AND REPLACED #1 SAFETY VALVE IN REF TO CRJ 900 AMM 21-32-03. PRESSURIZED A/C TO 4.0 DP IN REF TO CRJ 900 AMM 21-31-00 OPS CHECK GOOD AT THIS TIME WITH NORMAL OPERATION. (TC# 20190619006)