The email address associated with your Redgate ID cannot be changed in the customer portal, a new ID needs to be created.
First you will need to create a Redgate ID for the new email address that you'd like to use.
To transfer your licenses from the old account to the new one you will need to log in to the old account and add the new email address as an owner to each license.
In the portal choose Licenses:
The license information is broken down:
Select the license and click to expand the license information.
Click on the cog in the top right hand corner of your screen:
A new window will pop up entitled Manage owners and admins. Click +Add:
Enter the email address of the new owner and click the Owner tab.
Click Add to finishing adding the owner.
If you're a user you can raise a support ticket to request the transfer of any existing licenses from your old account to the new.
For more information on managing licenses, please visit this article: