  We calculate the one neutron removal reaction cross-section $(\sigma_{-1n})$
for few stable and neutron-rich halo nuclei with $^{12}$C as target, using
relativistic mean field (RMF) densities, in the frame work of Glauber model.The
results are compared with the experimental data. Study of the stable nuclei
with the deformed densities have shown a good agreement with the data,however,
it differs significantly for the halo nuclei. We observe that while estimating
the $\sigma_{-1n}$value from the difference of reaction cross-section of two
neighboring nuclei with mass number A and that of A-1 in an isotopic chain, we
get good agreement with the known experimental data for the halo cases.
