When a subscription report is created (for information how to save a report see the step by step guide on creating reports) it is saved into the saved report archive that you can access through the menu (Saved reports->List view). 
This page contains a list of all the saved reports that is associated with the currently logged in account. When there are a large number of reports in the list a filter can be applied to narrow down the result. The filter can be a part of an e-mail address or the name of the report. 
The checkbox View saved report for all users is only visible if your account is a member of the administrator roles.
When you want to edit a saved report or use a previously saved report as a template for a new saved report you start by clicking on the Report Name link on the left.
When the Report Name link is clicked on an administration panel is opened for the selected report.
On this panel many of the settings for the report can be changed. You can change when it's created and which period it should contain.
You can also edit who the receivers of the report should be and the export format that the report should be saved in before distribution.
For more information about the different distribution alternatives see the section saved reports.
On the right of the panel on the same side there are a couple of icons that lets you Execute the report as well as load it (same as executing it but you get the chance to tweak the settings before it is created). You can also send it to the receivers directly by clicking on the Send button. Note that when using send as a mail function the report is sent at that moment (the settings for when the report should be created are not used nor changed).
And of course you can remove the report from the system by clicking on the Delete button. 
Under the Columns tab the included columns in the report can be edited. 
Under the Subscribers tab the included subscribers and/or groups can be edited.