CODING AND DECODING

$H+2=J$

$E-2=C$

$R+2=T$

$C-2=A$

$U+2=W$

$L-2=J$

$E+2=G$

$S-2=Q$

$HERCULES \implies JCTAWJGQ$

Hence,

$A+2=C$

$P-2=N$

$H+2=J$

$O-2=M$

$R+2=T$

$D-2=B$

$I+2=K$

$T-2=R$

$E+2=G$

So, $APHORDITE \implies \boxed{CNJMTBKRG}$ .

Note: $+2$ and $-2$ mean moving $2$ letters ahead or $2$ letters back in the English alphabet.