User blog comment:FairyRaven/Fairy Tail Chapter 456: Orders, Review and Commentary/@comment-7418318-20151010140837/@comment-5268982-20151011065156

Lucy went into Aquarius star dress with a broken key. Sure, CSK lent her the power, but then again when she first used Urano Metria it was a lent power but she managed to make it hers. I think it will be something similar here, with Lucy going Aquarius Star Dress despite the key being broken.