[phenixbb] alternate conformation clashes with its symmetry mate

Dear phenix BB, I am having an alternate conformation clashing problem that I am having difficulty resolving: I have a protein in which the N-terminal residue is in two conformations.When the residue is in the 'A' conformation, the sidechain overlaps with the 'A' conformation sidechain density of its symmetry mate. I have modeled the occupancy at 50%. However, every time I refine, phenix pushes the 'A' conformer out of the density, likely due to clashing with its symmetry mate. Is there anyway to get around this? Thanks in advance, Rebecca