What is the role of eadem mutata in this phrase? I'm guessing either neuter plural accusative of extent, or feminine nominative as apposition to an implied ego. The original context of this line is limited and I couldn't find any detailed imformation about the background that prompted this phrase.
Without additional context I am inclined to view eadem mutata as an absolute ablative. Then your phrase eadem mutata resurgo would mean something like "I rise again when/because the same thing has changed". It is impossible to provide a good general translation without further context.
Let me extend your phrase a little bit to see how it could work in a fuller sentence. This extension is just an example I came up with, since I have no idea of the origin of the phrase.
Rerum condicio pessima erat et eius causa cecidi. At eadem mutata resurgo nunc.
The situation was very bad and I fell. But now that it (the situation) has changed, I rise again.
Rafael points to the Wikipedia article on the phrase in his comment below. The interpretation offered there is indeed grammatical; there are just numerous grammatical ways to read a short expression like this, and this makes context so important. In this reading a feminine ego is understood as the subject and eadem and mutata are appositions. The subject raises again, being both the same as before and changed. One can see this from many angles:
- "Although changed, I rise as the same."
- "Although the same, I rise changed."
- "I rise changed and unchanged."
- (and other options)