Changing or Deleting an Action 
You can change or delete scheduled actions in the DBA Planning Calendar.
If you want to change a periodic action, only future executions of the action will be affected. The action is divided into two: the old action and a new one.
Prerequisites
If you want to change or delete an action from the DBA Planning Calendar, it must be in the state Scheduled (that is, not already executed).
Note
If an action has already been executed, you can only display it. For more information, see Displaying Actions.
Procedure
Open the DBA Planning Calendar (Setting Up and Using the DBA Planning Calendar).
Changing an Action
Move the cursor to the calendar cell containing the desired action and select Edit.
A dialog box appears displaying the Action Parameters and entries for Repeat Intervals. Enter your changes.
You can schedule the changed action by selecting Change Current Scheduled Job or Change All Scheduled Jobs.
Deleting an Action
Place the cursor on the calendar cell containing the desired action. Choose Delete.
A dialog box appears listing all actions that can be deleted.
Select a task.
To delete an action, choose Delete.
Result
The DBA Planning Calendar's schedule is updated.