Scedule interacts directly with your calendar. With sending the invitation, Scedule synchronizes it (time, participants, location, Dial In information, ...) directly to your calendar. Your calendar will then send the invitation to all participants as usual. Scedule usually syncs with your default calendar. You can change this in the system settings of your smartphone and Outlook. According to this, your participants can accept or cancel as usual.
Therefore, Scedule is not another calendar and does not claim to replace it. Scedule extends it only by the so essential function of appointment coordination.