Note:
Because subscriptions are managed chronologically, you can open a previous version of a subscription. After you have saved a subscription, you can access previous versions of it that exist in the database. However, if you modify and save a previous version of a subscription, all later versions of it are deleted.
To open a previous version of a subscription, open the subscription as described in this topic. When the subscription is open, click the Change Version icon 
on the toolbar in the main window. The Change Version dialog box opens. Select a version of the subscription from the list, and then click View.
You can only delete a previous version of a subscription by modifying it, specifying an effective date earlier than the effective date of the original version, and then save the subscription.