Deleting a Recurrence
All users, except for collaborators, with whom the task is shared can delete the recurrence unless their access role restricts it.
Open any task that's part of the recurrence in Task view.
Click the task’s three-dot menu button in the upper right-hand corner.
Select Edit recurrence from the drop-down menu that appears.
Click Delete at the bottom of the pop-up that appears.
New recurrent tasks will no longer be created, and all tasks in the recurrence sequence that weren't manually edited are deleted.