Calendar Edit Event is located under My Calendar > Events. Click an event to edit. The main difference from Add Event to Edit Event is the following top menu items.

My Calendar > Events (Edit Event)

Delete – Delete the event.

Edit Event Post – My Calendar events are managed independently, via the My Calendar event manager. They use a custom post type to manage custom fields. This option makes it possible for custom field managers such as (e.g. Advanced Custom Fields) to add custom data to My Calendar events.

View – View the single event view for this event.

Events – Return to the event management screen.