Rescheduling events is a simple drag-and-drop operation:
Using the Date Navigator go to the date of the event that you want to reschedule.
You should choose an appropriate view before beginning this operation. Only the Agenda view (Day, Work Week and Week views) shows individual hours and are suitable for rescheduling exactly-timed events (appointments), while the Month view only shows days. Therefore the Month view is most suitable for long-term events like holidays.
To display the Week view select the Agenda view, press the view toolbar button, or choose the → menu item.
Drag and drop the event to the new date and time location.
If you wish to reschedule more precisely, double-click the event and change the start and end time using the drop down menus that divide the day into quarter hours. If that is not precision enough, you can enter the desired time directly.