In our previous work on BaFeO2.78 phase in situ electron diffraction and XRD data evidenced the structural changes involved in the reduction process of this sample. This study explored the reduction pathway of the 6H polytype from the most oxidized form, BaFeO2.96, to the most reduced one, BaFeO2.63. To better understand the evolution of the structure and the oxygen content variation during this redox process, an in situ neutron diffraction and electron microscopy study of the BaFeO2.96 oxide after treatment at different temperatures and gas environments (vacuum and air) is now performed.