What methods can contain ValueObject?

Question

EAV

In all primers, only
__toString, equals, getValue and that's all? For example, if I need to change the VO, the change?

class VOName{

public function change(string $value){
return new VOName($value);

Or should such a method contain an aggregate? Which consists of this VO?
What other methods can be and what are not, why?

Answer 1

ValueObject - may have a change method, but must only return a new value. For example, var fullName2 = fullName.ChangeLastName('Ivanov');
You can stick any subject logic there as well as in essence ...