To change options for an item that is not part of a series
To change options for all items of a series
To change options for one item that is part of a series
In Calendar, you can drag the appointment, event, or meeting to a different date. You can also edit the subject by clicking the description text and typing your changes.
You can change an event into an appointment, causing the time to be blocked out in your Calendar, by clearing the All day event check box and then entering start and end times. Events are defined as lasting from midnight to midnight; clearing this check box allows you to enter specific times.