Characters in Mrs. Frisby and the Rats of NIMH are transformed by their interactions with other characters, by their experiences, and, of course, they're transformed by science. The thread that connects all of these different types of transformation is knowledge. When the rats escape from NIMH, they don't simply flex their new muscles and scurry back to life as they knew it. Instead, they use their knowledge to transform their lives and their society. Mrs. Frisby's life is transformed by knowledge as well. Knowing the backstory on her husband opens up all sorts of possibilities for her and her children.
The rats cannot really take credit for the changes to their lives; it was all NIMH's doing.
NIMH gave the rats the tools to change, but it was their own ingenuity and perseverance that really allowed them to change their lives and create the Plan.