Neutron studies of the archetype Kondo-insulator compound YbB12 have revealed several intriguing features in its magnetic excitation spectrum. Below 10 K, the magnetic response exhibits a spin gap and several low-lying excitations, one of which, at E = 15 meV, bears interesting similarities with the "resonance mode" (RM) intensively studied in HTC superconductors and other materials. In previous experiments on IN22 and IN8, we have investigated the effect of an applied magnetic field and observed a decrease in the intensity of the RM peak at 10 T, together with a more pronounced localization of the mode in Q space near the AF L-point, q = (1/2, 1/2, 1/2). However, the run on IN8 was hampered by a number of sample-environment problems, resulting in substantial loss of beam-time, and serious unreliability in background corrections. We therefore apply for continuation beam time in order to confirm, complement, and precise the experimental data. Specifically we need to ascertain the effects of the field on the intensity, energy width, and Q dependence of the RM in YbB12.