The programming interface for windows phone 8.0 does not allow to edit or delete existing appointments. This is the reason why Week View uses a workaround to do this for appointments in windows live calendar.
It uses direct access to a users windows live calendar, if the user allows this and signs in to windows live inside the app, to edit/delete windows live appointments. Although this works it’s only the second best possible solution.
The best solution would be, if MS provides tasks to do this, like they already do for creating appointments: A „SaveAppointmentTask“ is provided to create appointments in all calendars that are configured on the phone.
But at the moment there is not task to edit/delete existing appointments. 🙁
Microsoft provides a „users voice“ page where users can post their suggestions, how to improve the windows phone platform.
The good news is: A feature request that is very important for creating great calendar apps was updated recently: API for change and delete calendar appointments
Thank you for the suggestion and the spirited commentary. We did not add this capability in the 8.0 release, but know that it is high on the consideration list for future Windows Phone releases.
I hope this feature will be added to the next windows phone OS update, which would be great for developers and users of the windows phone platform!