You can add additional managers to the site, and you will just need to follow the steps listed below to do so.
1. Go to the Account area within the site's control panel.
2. Click the "Add a Site Manager" link on the right side of the page.
3. Type in an email address for the new manager, and then click the "Send an Invitation" button.
4. Once the invitation is sent, the new manager should receive an email containing a link that will allow them to accept the invitation.
5. After clicking the link within the invitation email, the new manager should be able to log into the site to begin working on it.
*Note: Managers will have the ability to edit all areas of the site outside of the billing information.