Yes, you can edit the deadline via the Invitation page located near the top of your event page.
From the event page click on the Invitation button, you'll see a Submission Deadline field at the bottom.
Note: Contributors can continue to submit their videos and photos after the submission deadline has passed. The Event Page is only closed to submissions once you hit the Finalize button.
If you need further assistance, please contact a Customer Care Specialist using our live chat, found in the bottom right corner of the VidDay app or website.