AND if another actress who has a birth name the same would be forced to change it?
Happens all the time with actors.
Michael Keaton is Michael Keaton because his real name is Michael Douglas, and that one was taken.
William H. Macy had to add the H because William Macy had co-starred on Maude and had the name first.
Actually yes, or use a middle name. Kevin McCarthy, a talk show host in Dallas had to register using his middle name because actor Kevin McCarthy had trademarked and used his name in SAG/AFTRA.
AND if another actress who has a birth name the same would be forced to change it?
Actually that is true today. When an actor signs up for SAG and their real name conflicts with an existing actor’s name they must use a different one. As an example there was already a Michael Fox so when a new one came along he had to register as Michael J Fox.
That’s already the case by SAG rules. Michael Keaton was born Michael Douglas but he had to use a different stage name because Kurt Douglas’ son already had that one.