To edit or cancel a regular donation, log in to your MyGiving account.
On your dashboard, click on your name, and on the next screen select 'Donations' from the menu on the left-hand side.
Select the 'Regular donations' tab, and click 'Manage' next to the name of the regular donation:
On the following screen, to cancel, click 'Stop Regular Donation':
Confirm by clicking 'Stop' in the pop-up box.