Once you have started the event, any changes you wish to make need to be done on the event Dashboard. Once the change has been made, you will need internet access in order to refresh the event on the Snappic app so that your event reflects the new changes.
How to?
Once you have made the desired change to the event on the dashboard, exit the event on the Snappic app and press the Refresh button in the top right corner.
Once the event has refreshed you will be able to open it and resume.