A participant in the Unicode development process once complained: "If biologists had insisted that names once assigned could not be changed because of advances in knowledge, or even to correct errors, then surely the system would have broken down centuries ago."
But in fact, the international Linnaean names of plants and animals are not changed for either of those reasons, nor for any other reason whatsoever: though we now know that Basilosaurus is a proto-whale and not any sort of reptile, Basilosaurus it will remain forever.
The only thing that can happen in Linnaean nomenclature is the recognition that two names are synonymous. In that case, there is a question which shall be the preferred name, and normally it is the first name to be published, but exceptions sometimes occur. Thus when the dinosaurs Brontosaurus and Apatosaurus were found to be the same, Apatosaurus was chosen as the preferred name because it was published first; however, this is not properly to be described as "changing the name of Brontosaurus to Apatosaurus". Brontosaurus is a perfectly good name and may still be used even though it is dispreferred.
When are later names preferred to earlier ones? Usually when the earlier name has long been forgotten, and the later name is widely used in the scientific literature.