Comment by randomdata

You don’t change what is already defined (even if only by inference). Change is only by amendment. Will you successfully amend the changes without also changing what was previously defined if all you have is inference to go on? Probably not.

That’s assuming change is even necessary. Oftentimes you only need to modify the implementation, which doesn’t change what is defined. A change in implementation has no impact on the outside, at least as long as you have properly covered your bases, which should you should be able to do as long as you have proper documentation. Without documentation, good luck to you.