DataGuard SWITCH OVER
Phase 1 PRIMARY:
1) SELECT SWITCHOVER_STATUS FROM V$DATABASE;
2) /**** ALTER SYSTEM SET remote_archive_enable=RECEIVE SCOPE=SPFILE;/
ALTER DATABASE COMMIT TO SWITCHOVER TO STANDBY WITH SESSION SHUTDOWN; (If you get SESSIONS_ACTIVE in 1, otherwise not needed)
3) ALTER DATABASE COMMIT TO SWITCHOVER TO PHYSICAL STANDBY;
4) SHUTDOWN IMMEDIATE;
5) STARTUP NOMOUNT;
6) ALTER DATABASE MOUNT STANDBY DATABASE;
7) ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING CURRENT LOGFILE;

Phase 2 STANDBY:
1) SELECT SWITCHOVER_STATUS FROM V$DATABASE;
2) /****ALTER SYSTEM SET remote_archive_enable=SEND SCOPE=SPFILE;/
3) ALTER DATABASE COMMIT TO SWITCHOVER TO PRIMARY;
4) SHUTDOWN IMMEDIATE;
5) STARTUP;