Essential Appositives Nonessential Appositives  They are necessary for identifying the noun and pronoun they are renaming.  They provide additional information for the noun or pronoun they are renaming. They are not required for identification.  Commas are not required to set them off. Commas set them off. Example: My friend John is a doctor. "John" is essential to the meaning of the sentence, as it identifies which friend is being referred to. Example: John, my friend, is a doctor. "my friend" is nonessential to the meaning of the sentence, as the name "John" alone would still convey the necessary information.