The deviations of the ${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}$-induced neutron knockout cross section ratios from the impulse approximation, as measured in a recent deexcitation $\ensuremath{\gamma}$ ray experiment on $^{7}\mathrm{Li}$, are shown to be in good agreement with the modified nucleon charge exchange model with reasonable charge exchange probabilities.NUCLEAR REACTIONS Ratios of $\ensuremath{\sigma}[^{7}\mathrm{Li}({\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}, \ensuremath{\pi}N)^{6}\mathrm{Li}^{*}(3.56 \mathrm{MeV}]$, detect deexcitation $\ensuremath{\gamma}$, ${T}_{\ensuremath{\pi}}=50 \mathrm{to} 290$ MeV, probability of recoil nucleon charge exchange.