At
https://aka1908.com/membership/aspir...ective-members
Q: Can I seek membership if I am or was a member with another Sorority?
A: If that Sorority belongs to the National Pan-Hellenic Council or National Panhellenic Conference, you are ineligible for membership with Alpha Kappa Alpha. Individuals that falsify applications will have their membership revoked and will be expelled from the Sorority.
I presume the OP meant NPC when they said PHA, but some campuses may have non-NPC members of the PHA. At this point, contacting AKA National seems to logical next step to see if *anything* can be done.
(As a note, DST's website also specifically mentions NPC sororities as not allowing double membership, ZPhiB and SGR do not, but I take that as *no* assurance that a Sigma Kappa could become ZPhiB or SGR, merely that perhaps not all membership requirements are listed in obvious public places on those two websites.)