How To Reword A Sentence That Ends In A Preposition. You should leave it off. In the same way that one should not say, where is the book at? it should be, where is the book? there is no need for at, and it is redundant.
Let's look at an example: The direct object of the verb is the one who lost something. In the same way that one should not say, where is the book at? it should be, where is the book? there is no need for at, and it is redundant.
That said, if you are writing for a teacher or an editor who insists that you follow this rule, the conventional way to comply is to reword the sentence to say for which, with which referring back to the appropriate word.
It is wrong for that reason, not because it ends the sentence with a preposition. Ending a sentence with a preposition a preposition typically sits before a noun to show the noun's relationship with another nearby word. That's the best reason to avoid a preposition at the end of a sentence. However, regardless of where you choose to place the prepositional phrase, be sure to place it as close as possible to the word it modifies ;