SQL> show parameter db_recovery

NAME				     TYPE	 VALUE
------------------------------------ ----------- ------------------------------
db_recovery_file_dest		     string	 /oradata/prbwh/flashback
db_recovery_file_dest_size	     big integer 50G

SQL> alter database flashback ON;
alter database flashback ON
*
ERROR at line 1:
ORA-01153: an incompatible media recovery is active

SQL> select thread#, max(sequence#) from v$archived_log group by thread# order by 1;

   THREAD# MAX(SEQUENCE#)
---------- --------------
	 1	      131

SQL> select thread#, max(sequence#) from v$archived_log where applied='YES' group by thread# order by 1;

no rows selected

SQL> alter database recover managed standby database cancel;

Database altered.

SQL> alter database flashback ON;
alter database flashback ON
*
ERROR at line 1:
ORA-38706: Cannot turn on FLASHBACK DATABASE logging.
ORA-38788: More standby database recovery is needed

RMAN> Reset database to incarnation 1;