SQL> select group#,status from v$log;

GROUP# STATUS
---------- ----------------
1 CLEARING_CURRENT
3 CLEARING
2 CLEARING
SQL> alter database recover managed standby database cancel;
Database altered.
SQL> select group#,member,status from v$logfile;
GROUP# MEMBER STATUS
---------- -------------------------------------------------- -------
1 /u01/app/oracle/prod/disk1/redo01.log
2 /u01/app/oracle/prod/disk1/redo02.log
3 /u01/app/oracle/prod/disk1/redo03.log
4 /u01/app/oracle/prod/disk1/standbylog1.log
5 /u01/app/oracle/prod/disk1/standbylog2.log
6 /u01/app/oracle/prod/disk1/standbylog3.log
7 /u01/app/oracle/prod/disk1/standbylog4.log
1 /u01/app/oracle/prod/disk2/log1b.log
2 /u01/app/oracle/prod/disk2/log2b.log
3 /u01/app/oracle/prod/disk2/log3b.log
10 rows selected.
SQL> select group#,status from v$log;
GROUP# STATUS
---------- ----------------
1 CLEARING_CURRENT
3 CLEARING
2 CLEARING

SQL> alter database drop logfile member '/u01/app/oracle/prod/disk2/log2b.log';
alter database drop logfile member '/u01/app/oracle/prod/disk2/log2b.log'
*
ERROR at line 1:
ORA-01275: Operation DROP LOG MEMBER is not allowed if standby file management
is automatic.

SQL> show parameter standby

NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
standby_archive_dest string /dbs/arch
standby_file_management string AUTO
SQL> alter system set standby_file_management='manual';
System altered.

SQL> alter database drop logfile member '/u01/app/oracle/prod/disk2/log2b.log';
Database altered.

SQL> alter database drop logfile member '/u01/app/oracle/prod/disk2/log1b.log';
alter database drop logfile member '/u01/app/oracle/prod/disk2/log1b.log'
*
ERROR at line 1:
ORA-01609: log 1 is the current log for thread 1 - cannot drop members
ORA-00312: online log 1 thread 1: '/u01/app/oracle/prod/disk1/redo01.log'
ORA-00312: online log 1 thread 1: '/u01/app/oracle/prod/disk2/log1b.log'

SQL> alter database drop logfile member '/u01