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Just from the information you've provided, it seems you're creating a convoluted and potentially confusing situation for no good reason. If, however, this is important to the story, you can always ...
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#3: Attribution notice added
Source: https://writers.stackexchange.com/a/2482 License name: CC BY-SA 3.0 License URL: https://creativecommons.org/licenses/by-sa/3.0/
#2: Initial revision
Just from the information you've provided, it seems you're creating a convoluted and potentially confusing situation for no good reason. If, however, this is important to the story, you can always refer to "Earth" (formerly "New Earth") and to "Old Earth". Using a slightly different version of the word would work, but I believe that's already been done: Gene Wolfe's "Urth", and possibly elsewhere. I'd rename the new planet to something else if possible.