This Oracle tutorial explains how to use the Oracle/PLSQL TO_MULTI_BYTE function.
The Oracle/PLSQL TO_MULTI_BYTE function converts character value with single-byte characters to multibyte characters.
To use this function, the database character set must contain both single-byte and multibyte characters.
TO_MULTI_BYTE(x)
converts the single-byte characters in x to
the corresponding multi-byte characters.
The syntax for the Oracle/PLSQL TO_MULTI_BYTE function is:
TO_MULTI_BYTE( char )
char can be a char, varchar2, nchar, or nvarchar2 value.
SQL> select to_multi_byte('this is a test') from dual;
TO_MULTI_BYTE(
--------------
this is a test
SQL>