Porting Mobile Number from one Xfinity account to another Xfinity account

My mother-in-law has lived with us for several years.  I had originally added a line to our Xfinity Mobile account and ported her number over.  She recently moved out and we established Internet and TV through Xfinity at her apartment.  She is receiving emails and offers regarding one free year of Xfinity Mobile Service if she ports her number over.  I have two questions. First, can we port her number from my Xfinity Account to her Xfinity account without any issues? Second, since the line is being ported from another Xfinity account, will she still be eligible for the one-year free service offer?    Thank you.