Changing and deleting scheduled items is performed in item-level displays. As illustrated in the preceding section of the requirements, all item-level displays have `Change' and `Delete' command buttons to perform these operations. The enabled/disabled state of these buttons is consistent in all four types of item. Specifically, when the system initially displays an item-level view, the `Change' and `Clear' buttons are disabled and the `Delete' button is enabled. This is illustrated in the display excerpt shown in Figure 104.

As soon as the user performs an edit to some data field, the initial state of the command buttons is reversed. Namely, the `Change' and `Clear' buttons are enabled and the `Delete' button is disabled. This is illustrated in Figure 105.

When the user executes and confirms `Delete', the system removes the item from the affected calendar(s), removes the item-level display from the screen, and updates any affected display windows.

Since the different types of scheduled item share many data fields in common, many aspects of changing items are common to all types. Aspects of item deletion are also common among the different types of item, such as the general form of the confirmation dialogs. The most wide-ranging effects of change and delete are made to meetings by meeting schedulers. Such changes and deletions potentially affect all attending users.

NOTE: Details need to be filled in, as outlined in the following subsections.

2.5.2.1. Changing and Deleting Appointments

The change and delete commands for meetings behave much the same as they do for appointments. The significant difference is when a scheduler changes a critical meeting data field or deletes a meeting, all attendees are notified. Scheduler deletion of a meeting is the means by which the meeting is effectively cancelled.

2.5.2.3. Changing and Deleting Tasks