Change of Primary Domain in Google Apps
- Login to your Google Apps Control Panel.
 - Browse to Google Apps API Page where you change customer information. Make sure you see your Admin email address in to right corner.
 - Click “Try it now” link.
 - In “customerKey” field enter “my_customer“.
 - In “fields” field enter “customerDomain“.
 - Click “Request body” field, a drop down box will appear & select “customerDomain“.
 - In the newly appear field, enter your Secondary Domain which you want to change to Primary Domain.
 - Finally click the blue “AUTHORIZE AND EXECUTE” button.
 - When the process is done, your secondary domain is converted to Primary Domain and vise versa.