I believe that the appositive phrase would be "the one with the white blaze" as this renames "that horse" . I hop this helped, and please rate brainliest! Have a nice day!
Answer: The appositive phrase is<u> "the one with the white blaze"</u> and the word that this phrase renames is <u>"horse". </u>
Explanation: An appositive phrase is a group of words that act together to rename another word/words found right before or right after this phrase. Appositive phrases usually rename nouns or pronouns. Moreover, they are always separated from the rest of the elements in the sentence by means of commas. In the sentence provided,<u> "the one with the white blaze" is an appositive phrase since it has been set off from the rest of the sentence with commas and it has been included to rename the noun "horse"</u>, which was placed right before it.