As a Linux system administrator (administrator or root) you can change the password for any users on your server. To change a password on behalf of a user:

1. First, sign on or “su” or “sudo” to the “root” account on Linux, run:  sudo -i and enter the password.

2. Then type passwd username to change a password for a specific user. For example, run  passwd root   or  passwd administrator to change the password of user "root" or "administrator". Or type passwd to change the password of the current user. The system will prompt you to enter a password twice.

3. Log into your server again using the new password for verification.