You don't graduate until the day of your convocation (whether you attend or not). On the registrar's website there's a "graduand information centre" that is made available a certain number of months prior to the fall and spring convocations. You have to fill that out to inform the registrar of your intent to graduate, and that's it.
Although apparently they force you to graduate at the next ceremony as soon as you have all the requirements anyways, it's better to just fill out the online form anyways