A legal change is not required unless the purpose of the change is fraudulent or in other ways criminal.
Sue
Looking back at the way I have expressed that (above) is a bit clumsy.
My meaning is..
You can call yourself whatever name you like in our country.
If, however, you call yourself a different name for the purpose of doing something illegal, it is then a crime.
This previous Rootschat thread may interest you.
https://www.rootschat.com/forum/index.php?topic=840105.0Sue