On PRIMARY

— Convert primary database to standby

CONNECT / AS SYSDBA
ALTER DATABASE COMMIT TO SWITCHOVER TO STANDBY;

-- Shutdown primary database
SHUTDOWN IMMEDIATE;

— Mount old primary database as standby database

STARTUP NOMOUNT;
ALTER DATABASE MOUNT STANDBY DATABASE;
ALTER DATABASE RECOVER MANAGED STANDBY DATABASE DISCONNECT FROM SESSION;

On STANDBY

— Convert standby database to primary

CONNECT / AS SYSDBA
ALTER DATABASE COMMIT TO SWITCHOVER TO PRIMARY;

— Shutdown standby database

SHUTDOWN IMMEDIATE;

— Open old standby database as primary

STARTUP;