We have recently performed zero field muon spin rotation (muSR) studies of one the shape memory alloy Ni2.04Mn1.4Sn0.56 on EMU spectrometer at ISIS and the observed results are quite interesting. The multiple magnetic transitions are beautifully depicted in the muSR data. Most importantly, it clears some of the doubts regarding the thermal variation of different magnetic phases. The alloy is characterized by strong magnetic field induced magneto-structural transition which is the key to its functional properties. It is essential that one should study the similar muSR in presence of suitable longitudinal magnetic field. Considering rich phase diagram with respect to magnetic field and temperature, we propose to perform muSR study under 50 kOe of magnetic field on the same alloy along with two more related compositions in HIFI spectrometer in the temperature window 10-350 K.