A Group Manager or System Manager has the ability to assign another user as an Event Manager during the event creation process by adding the event manager under the Manager(s) section on the right side  or after an event has been published. 

Follow the steps below in order to add an Event Manager to a published event:
1. Click on the Manage tab
2. Click Manage Events, 
3. Search for the event you wish to add an event manager
4. Click the pencil next to the event on the right to edit the event
5. Under Manager(s) Click the magnifying glass to search for an Event Manager.
6. Enter the users first and last name
7. Click the Search button
8. Select the users name 
9. Click Apply & Close
10. Save the Event when finished