Your subscription for Microsoft Office is for a specific period, and will expire after a certain date. As your subscription nears the expiration date, you will be reminded to renew your subscription.
If your subscription expires before you renew, Microsoft Office will go into Reduced Functionality Mode. In that mode you will not be able to create new documents or save changes to existing documents, and additional functionality may be reduced. No existing Office files will be harmed.
You may renew or extend your subscription at any time either using a credit card or a new subscription CD (with product key) purchased from your local authorized Microsoft retailer. You can complete the subscription renewal process via the Internet or by telephone. To access the Office Activation Wizard and process a subscription renewal, from the Help menu of any application, choose Activate and then follow the steps in the wizard.