Change of ID and keep content

I don't know about Rush, but Lightroom Classic is not an issue as you can simply sign-in to the Adobe Creative Cloud app using your new account ID and then LrC can be used as normal. There's nothing that ties the LrC catalog and images to a specific account ID.....unless you are also syncing images to the Adobe cloud. Anything that you have stored in the cloud IS tied to the specific email address that was used at the time, so changing the account ID will make it more difficult to access. So let us know if you have been syncing a Classic catalog with the cloud and we can perhaps explain what you would need to do.