It's probably Partner Messaging R7.0 then. To change a password you need access to the administrator's menu. Below are the log-in instructions:
Press the vma button on your phone or dial 777
When prompted for an extension: 0#
When prompted for a password: Enter the admin password
Press 9 (this is a hidden option you will not be prompted for)
Press 2 for Extensions
Enter extension number and #
Press 3 to set the password to #
The next time you log-in, use # for the password, it will then prompt you for a new password
You are not supposed to put admin passwords on this site. A simple search on the internet for Partner Messaging R7.0 should get you the default password. If the default doesn't work you may need to call someone who works on the Partner system as there is a backdoor way to reset the admin password to gain access.