SQL> show user
USER is "SYS"
SQL> select username,password from dba_users
  2  where username='SCOTT';

USERNAME                       PASSWORD
------------------------------ ------------------------------
SCOTT                          F894844C34402B67

SQL> alter user scott identified by yourpassword;

User altered.

SQL> conn scott/yourpassword
Connected.
SQL> show user
USER is "SCOTT"
SQL> create table newtab(n1 number,n2 varchar2(20));

Table created.

SQL> conn sys as sysdba
Enter password: *****
Connected.
SQL> alter user scott identified by values 'F894844C34402B67';

User altered.

SQL> alter session set current_schema = <other_schema_name>;