Well..in my university I studied Noun phrase modifier separately from Appositives like this:
Noun phrase modifier: is a word, phrase,clause that modifies or describes a noun including a pronoun or a noun phrase.For example :
-The CHILD actor won an award.
-We reserved twenty HOTEL rooms.
Appositives: is a word, phrase,or clause that modifies or EXPLAINS ANOTHER NOUN PHRASE.
For example
-My grandfather,THE FARMER,bought more farm land.
-The teacher,MY UNCLE, assigns a lot of homework.
That's what I studied at university if it is wrong so please explain it:-\