Using a successful framework for describing S-wave hadronic decays of light hyperons induced by a subprocess $s to u (bar u d)$, we presented recently a model-independent calculation of the amplitude and branching ratio for $Xi^-_b to Lambda_b pi^-$ in agreement with a LHCb measurement. The same quark process contributes to $Xi^0_c to Lambda_c pi^-$, while a second term from the subprocess $cs to cd$ has been related by Voloshin to differences among total decay rates of charmed baryons. We calculate this term and find it to have a magnitude approximately equal to the $s to u (bar u d)$ term. We argue for a negligible relative phase between these two contributions, potentially due to final state interactions. However, we do not know whether they interfere destructively or constructively. For constructive interference one predicts ${cal B}(Xi_c^0 to Lambda_c pi^-) = (1.94 pm 0.70)times 10^{-3}$ and ${cal B}(Xi_c^+ to Lambda_c pi^0) = (3.86 pm 1.35)times 10^{-3}$. For destructive interference, the respective branching fractions are expected to be less than about $10^{-4}$ and $2 times 10^{-4}$.
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