You can add an admin to your Org Profile with an invite link.
Tap your profile picture (in the top-right of your screen)
Tap Settings
Tap Manage admins
You can now Add admin via link with a copy/paste-able link. Or, directly invite your cohost by clicking Add admin.
If you are not already Mutuals with your cohost, you'll need to have the admin RSVP to the event! Once they've RSVP'd, they'll be recorded as a Mutual with your Org Profile. Then you'll be able to add them by following these steps.