You/she may have to go into her account and remove her as administrator. Pretty sure only an administrator can remove their permissions and give permission to others, just like on a PC. Maybe you are both administrators. Traditionally, only and administrator can make someone else one, and the one who sets up the device usually has administrator privileges. What makes it a problem as to which one of you is the administrator? You don't want her to have control over the device, or you want to have control over her use of the device?
