We investigate an exchange biased polycrystalline IrMn/CoFe sample, measuring along each full magnetization loop as we vary the direction θ of the applied field Ha with respect to the unidirectional anisotropy direction or the field cooling HFC direction. Measurements are done using specular and off-specular polarized neutron scattering for increasing (negative to positive) and decreasing (positive to negative) field sweeping directions of Ha with respect to the negative direction of H FC. For both the angles θ ≤ 45° and 90°, remagnetization behaviours of all ferromagnetic layers occur simultaneously in a uniform mode (via coherent rotation) only. This is in contrast to the nonuniform reversal (via domain wall motion) previously observed by us for θ ≤ 0°. These variations of the relative strengths of the uniaxial and exchange anisotropies are thus found to be responsible for the reversal of magnetization via coherent rotation or via domain wall motion. Interestingly, off-specular spin-flip scattering shows that coherent rotation (where a significant specular spin-flip signal is observed) is accompanied by underlying concomitant in-plane magnetization fluctuations during reversal for both loop branches. These fluctuations - linked to the magnetization reversal - indicate the fluctuations from domain to domain in the system.