It can’t change a word to the same word. It must be a different word.

It only changes what is printed on the card (or set on a token when it was created or set by a copy effect). It will not change any effects that are on the permanent.

Can target a card with no appropriate words on it, or even one with no words at all.

You can’t change proper nouns (i.e. card names) such as “Island Fish Jasconius”.

You choose the words to change on resolution.

Alters all occurrences of the chosen word in the text box and the type line of the given card.

It can be used to change a land’s type from one basic land type to another. For example, Forest can be changed to Island so it produces blue mana. It doesn’t change the name of any permanent.