You can delete an open or closed status task from an open status schedule that might not be needed in a close cycle or was added in error. A task cannot be deleted from a Locked schedule.
To delete a task from a schedule:
Select Manage then Schedules.
Open a schedule in a view, such as Calendar-Month.
Right click on the task and select Delete.
If you delete the last open predecessor task, the next logical successor task will automatically be opened.