I need a user is an administrator, create a new event, and that a standard user can only edit the event, not even to create new events or delete, or edit or delete a series of events.

 For example, I create an event as an administrator. I want a user i created, can modify the event, and to extend such a day, but do not want the user to have access to delete it, or creating new events.

I can not find the means to do so, since the only way is that you either give the user access to all (add, delete, or edit) or losing access to perform any action.

 Please, help... Thanks!!