JennyW,
Sure there is, but you would need to have a button setup for the Voice Mail application or know the extension number for the Voice Mail application. By default this is typically 2500, but it depends on the vendor and how they configure their systems as the extension numbering plan can be set to anything.
1. Dial or Press Voice Mail button. This is not the Message Notification button that lights up when you get a message.
2. Press * to let it know you are a Subscriber
3. Dial your Extension Number
4. Dial your Passcode
This can be done from any phone as well.
Thanks,
TE