In the proposed experiment we suggest to study two La2O3(Fe1-xMnx)2Se2 x = 0.9 and x =0.95 systems that exhibit different AF structures at low temperatures using D20 and Paris-Edinburgh pressure cell. The two AF structures that have nearly the same phase transition temperature, differ in the direction of the Fe/Mn moments with respect to the tetragonal axis. Electronic structure calculations suggest that it should be possible to change the moment directions under pressure. It is the aim to determine the pressure dependence of crystallographic parameters (especially of the interatomic distances and bond angles) and bring the in relation with magnetic structure. We would like to know whether it would be possible to switch the direction of Fe/Mn moments under pressure before eventually destroying the AF order or modifying the crystal structure. We ask for 4 days on D20.