E.F. Buckles > Status Update

My reading challenge numbers keep getting inflated because Mom inherited my old Kindle after she got me a new one for Christmas (It's her first ever e-reader) and when she finishes a book, it's marking it read on my GR challenge. I'm not sure if there's any way I can disconnect my old kindle from GR without disconnecting my new one, too... So I keep having to go into my challenge and remove her finished books LOL.