From the “Settings” subsection of your “Edit” section, you can change the end date of your campaign. You must select a date at least one day after today’s date.
If your campaign has already ended, you can still change the end date, but you must first make sure that the status of your campaign is ”published”. If you have already closed your campaign, you will not be able to change the end date.
Remember to confirm any change by clicking on the button “OK, save” at the end.