After you have created a widget you can go back and edit the date that you want this widget to display at any time.
When on your dashboard, hover over the widget you wish to edit.
Click the thee dots in the bottom right-hand corner of the widget and click Edit Widget.
You will be transported back into the widget configuration screen.
From here you can edit the date and the comparison date.
Once you have made changes to your widget, click Save Changes and you will be transported back to your dashboard screen
Please note: Editing the date of a widget will cause you to lose any historic data.