To bulk edit your programs, navigate to Programs on the horizontal top menu and select Programs from the dropdown menu.
To edit multiple programs at once, select the checkboxes in the table next to each program and click the green Group Actions button that appears at the bottom of the page. Then select Edit Programs.
In the program editor, check the box next to the item that you want to override for all programs currently selected. Only attributes that you've checked will be overridden. Anything that you check and update will override all existing information for the given programs.
If you are updating the dates/deadlines, be sure to also override the Timezone for Dates field. You must select a time zone in order to override any deadlines.
When you are finished, click the Save & Next button at the bottom of the window. A popup window will confirm if you want to override these programs.