Historical Rules · 5 October 2018
Rule 612.2a
Official source text from the 5 October 2018 Rules release
Most spells and abilities that create creature tokens use creature types to define both the creature types and the names of the tokens. A text-changing effect that affects such a spell or an object with such an ability can change these words because they’re being used as creature types, even though they’re also being used as names.