What is the conjugate acid of ${\mathrm{HPO}}_4^{2-}$?

Conjugate acid of ${\mathrm{HPO}}_4^{2-}$ = ${\mathrm{H}}_2{\mathrm{PO}}_4^{-}$

The reaction is,

${\mathrm{H}}_2{\mathrm{PO}}_4^{-}\to {\mathrm{H}}^{+}+{\mathrm{HPO}}_4^{2-}$

The only proton that separates the base from its corresponding acid is that.