Set Current User to Another Schema

conn /@testdb as sysdba
alter session set current_schema = scott;

col current_user format a20
col current_schema format a20

select sys_context('USERENV','current_user') as current_user,sys_context('USERENV','current_schema') as current_schema from dual;

CURRENT_USER         CURRENT_SCHEMA
------------------------          ------------------------------
SYS                                   SCOTT