Form ST-12A: Certain purchasers may claim refund of tax paid to vendors. Before refund is paid to purchaser, this form must be executed by vendor and attached to purchaser's Form ST-12.
Ga. Comp. R. & Regs. R. 560-12-3-.18
Ga. Code Ann. Secs. 92-3438a, 92-8405, 90-8406, 92-8409, 92-8427.