Oracle Error ORA-12716: Cannot ALTER DATABASE CHARACTER SET when CLOB data exists

Oracle Error Message

ORA-12716: Cannot ALTER DATABASE CHARACTER SET when CLOB data exists

Reason for the Error

CLOB data changes representation to Unicode when converting to a multibyte character set and must be migrated

Solution

Remove CLOB data as listed in the alert file. CLOB data can be migrated by methods such as import/export