after the whole "sickness" that Ney had, she (unwillingly) got some new things, besides the memory card buried in the center of her head, she got the ability to fuse with Tei and Zoey by absorbing their bodies onto hers, she grows 2 extra pairs of wings and becomes bigger.
btw "taking the lead" is the process that they can use to switch control of the body, it cannot be taken, it must be given, Tei is control of the body now while Ney and Zoey are just voices in her head.