Angelwings does not formally appear in Hidden Prophecies, but is listed in the allegiances.
When Gaysparkle wants to join SapphireClan to be with his mate Tranquildream, Sparklestar, SapphireClan's leader, doesn't think it is a good idea. She tells Gaysparkle that he has to be his clan's medicine cat as Gaysparkle's mentor, Troubletail, died and he is the only medicine cat left in DiamondClan. Gaysparkle replies matter-of-factly that it's okay if he isn't their medicine cat because he thinks he heard that Angelwings, a cat that was his friend back in DiamondClan, said she wanted to become a medicine cat. He also adds that he thinks she would be a good medicine cat because she knew a lot about things.
It is possible that she is the same cat as Angelspirit, as Angelspirit is a she-cat that appears in the combined clan of DiamondClan and SapphireClan, but this is unconfirmed. If this is true, it is unknown if Tainted Purification forgot that she had already given Angelpaw a warrior name or if her name was purposely changed for another reason.
Gaysparkle: "Sparklestar does not mind that I'm here now right?"
Sparklestar: "I do not think that this is a good idea Gaysparkle. You have your own Clan and you have to be their medicine cat since I heard that Troubletail is dead. Is he dead?"
Gaysparkle: "Yeah he died. That's okay though because I think that I heard Angelwings say that she wanted to become a medicine cat. I think she would be a good medicine cat we were friends and she seemed like she knew a lot about stuff."
—Gaysparkle explaining how Angelwings could become the new medicine cat of EmeraldClan Hidden