I am a Zivver admin
Configure and manage Zivver
Merge accounts
You cannot undo the merge.
Open the accounts page in the Zivver WebApp.
Highlight the account that you want to process. Then, click Edit
Scroll to Mail aliases.
Enter an existing account.
Select a claimed domain.
Click Add alias.
In the new window, click Merge.
Make the alias that you set the primary email address.