You can invite someone to be a host of your event. If you are a host, you can also invite someone else to be a co-host. For live-stream enabled events, a host will have access to the publisher stage and live streaming tools.
To invite a host, go to your event, click the button with ... and then select the Invite Hosts option.

You can invite someone by simply using their email address. Type in the correct email address and then press Invite.

You can also look up someone with an exiting account by their name as shown below. To narrow you search, please type first-name<space>last-name to use both parts of their name to match.

Your invitee will receive an email with the invitation link that they would need to accept in order to become a host of the event.
If you wish to remove an existing host, find them in the Current Hosts list, click Delete below their picture and confirm.