Google Workspace – Change Primary Domain Without Losing Free Account

EDIT

My original answer is obsolete at this time. See Change your primary domain from the Admin console

Thanks Rubén for the heads up!

Unfortunately, you can't do this without having to create a new Google Apps account.

From [this Google Apps article][1]:

You can associate additional domain names with your Google Apps account, as separate domains or as domain aliases for your primary domain. However, at this time you can't change which domain is your primary domain. Your only option for a new primary domain is to create a new account and migrate your data to the new account.

In summary, for you to make DomainB your primary domain and DomainA as an alias you would have to:

• Remove DomainB as an alias from your existing Google Apps account
• Create a new Google Apps account with DomainB as the primary domain
• Migrate your data from your existing Google Apps account to your new Google Apps account
• Delete your old Google Apps account
• Add in DomainA as an alias to your new Google Apps account

Important Note:

If you've already purchased a Google Apps for Business subscription for your current primary domain, you can't transfer your subscription to a new domain name. When you create a new Google Apps for Business account for a new domain name, you will be charged for each user account that you create. If you do not want to purchase Google Apps for Business for two separate domain names, disable automatic renewals on your current account and make the change at the end of your current subscription.

The full steps for this process are:

1. Create a new account with the new primary domain.
   
   Sign up for and create a Google Apps account for your new domain name at http://www.google.com/a/.
   
   The domain name must not be associated with any existing Google Apps account. If it is associated with an existing account, you must remove it before creating the new account.
   
   
2. Migrate your data to the new account.
   
   Use one of the email migration options to transfer mail from accounts in your old domain to your new domain. Export any documents, spreadsheets, and presentations you would like to retain and upload them into your new domain, or share them with a user account in the new domain and copy them.
   
   Note: We do not offer migration options for Google Sites. Instead we recommend that you use one of our alternative methods to perform that function:
   
   1. Create a back up for the content in Docs and recreate the site once you register with the new domain name.
   2. Add the new domain admin as owner of the site and then copy it inside of the new domain.
   3. For those using the Sites API, you can go here for the migration options that are available to you: http://code.google.com/p/google-sites-liberation/
   
   
3. Delete your old account.
   
   Once all of your data has been transferred or backed up, delete the Google Apps account for your old domain. It takes five days for the account to be removed from our system.
   
   
4. (Optional) Add the previous primary domain to your new Google Apps account.
   
   If you want to retain the old primary domain as a non-primary domain with access to your Google Apps functionality, add it to the new account.

[1]: http://www.google.com/support/a/bin/answer.py?answer=54819

Unfortunately, there's no completely automated approach to this. Either you or your users will need to follow this approach:

1. "Re-name" all of the users on the domain you want to migrate. Re-naming actually gives you the option to change which domain a user account is part of. See Google Help Article.
2. Once you've moved all the users to your main domain, you can delete that domain from the original (temporary) google Apps account. Because none of the users have been deleted, all of their email, calendar, docs, etc. will still exist in that account.
3. Create the new Google Apps account with that domain name
4. Create user accounts for all of those users in the new Google Apps account
5. Use Gmail-Backup to backup all of the users' emails, and then use the same tool to restore those emails (together with all labels) to their new account. If you're doing this yourself, you'll need to temporarily set all of the users passwords to something you have access to.
6. If necessary, you can also log in to each of those user accounts and export their mail filters and then re-import them on their new accounts.
7. Go into calendar settings in each users Google Calendar account, and "share" each of the users calendars with their new account. Give them access to "make changes and manage sharing". If this doesn't work, it's probably because your current Google Apps account has the calendar settings too restrictive, you need to be able to share calendars with users outside this organization (namely your new Google Apps account)
8. Go into Google Docs for each user, and go to "All Items" under "More" on the left. Scroll to the bottom and make sure that all items have finished loading. Then select all docs using the checkbox at the top left and then select "sharing". Share all of these Google Docs with the users new account. Again, you may encounter restrictions from your original domain that you have to remove. You also may encounter issues sharing documents that were originally shared with this user by someone else. In that case you may have to share all of that users' own Google Docs with their new account, and then handle individually the items that were shared with them by others.

There is (unfortunately) no other way that I know of to transfer an account from one Google Apps domain to another. Although there are many steps here, it's not a very big job unless you have many users.