As I said, you have to tune the near-field distribution of the antenna. If is an embedded antenna (PIFA for example) shall be easier to play with this distribution, compared with an external antenna (helix or dipole-derivate).
Just for a quick indication you can do a relative measurement of this distribution, moving a small RF probe all around, at the same distance where the human-body model is located.
Sometimes if is a bad design, the human-body model de-tune the antenna, VSWR is going high, the reflected waves find a different radiation path in the mobile making the SAR test to fail.