How to remove the expired password in Oracle 11g or No access to Enterprise Manager

If you are trying to connect to the Oracle enterprise Manger and you get the following errors:
Enterprise Manager is not able to connect to the database instance, and in the “Agent connection to instance” section:
Status: Failed
Details: ORA-28001: the password has expired (DBD ERROR: OCISessionBegin)
Run cmd (command prompt)

• SET ORACLE_SID= <The database SID>

Run SQL*Plus

ALTER USER sys IDENTIFIED BY new_password;
ALTER USER dbsnmp IDENTIFIED BY new_password;
ALTER USER sysman IDENTIFIED BY new_password;
ALTER USER system IDENTIFIED BY new_password;
ALTER PROFILE DEFAULT LIMIT password_life_time UNLIMITED;
SELECT username,ACCOUNT_STATUS,EXPIRY_DATE FROM dba_users;

If no access to Enterprise Manager (extra settings):
Go to ORACLE_HOME//sysman/config and save a backup of the emoms.properties file.

1. Stop the dbconsole: emctl stop dbconsole
2. Open the file emoms.properties and search for:
   oracle.sysman.eml.mntr.emdRepPwd=
   Replace the encrypted value with the new password value
3. Search for oracle.sysman.eml.mntr.emdRepPwdEncrypted=TRUE
   and change TRUE to FALSE
4. Save and close emoms.properties
5. Restart the dbconsole: emctl start dbconsole