The presiding officer may upon motion, at any time during the course of the proceeding, permit such substitution of parties as justice may require.
Ga. Comp. R. & Regs. R. 20-14-.24
O.C.G.A. Secs. 43-3-8, 43-3-20, 43-3-21, 43-3-22, 43-3-23, 43-3-24, 43-3-28.