"Rules Text" defines the abilities of a card. Rules text is not always perfectly consistent in exact terms used, but most terminology remains the same. For example, one card might say "Choose 1 creature" and another "Select a creature", but both mean the same thing and have the same outcome.
While not technically a reprint, some cards may appear as a newer version if it is printed again in the same product as a new edition. In such a case, a card might have slightly updated text, but the effect and outcome should remain the same as erratas have never been issued in the game.