  We analyze the broad H$\beta$ line profile variability of the "changing look"
active galactic nucleus (CL-AGN) NGC 3516 over a long period of 25 years. The
observed change in the broad line profile may indicate a change in the geometry
of the broad line region (BLR). Using spectral line profiles, we aim to explore
changes in the kinematics and dimensions of the BLR in NGC 3516. We consider
two possible scenarios, i.e. changes in the broad-line emission are caused by a
decrease of ionization continuum emission or by the BLR obscuration by outer
dusty regions. With this investigation we aim to clarify the CL mechanism of
this AGN. We analyze the spectral band around the H$\beta$ line as well as the
broad H$\beta$ line parameters, and how they change in time. We model the
broad-line profiles assuming that there is an emission from the accretion disc
superposed with an emission from a surrounding region that is outside the disc.
We find that in the Type 1 activity phase, the BLR is very complex. There is a
clear disc-like BLR that contributes to the broad line wings and an additional
intermediate line region (ILR) that contributes to the line core. In the high
activity phase, the ILR emission is close to the center of the line (in some
cases slightly shifted to the red), whereas in the low activity phase (i.e.,
Type 2 phase), the ILR component has a significant shift to the blue,
indicating an outflow. We propose that the changing look mechanism in NGC 3516
is rather connected with the intrinsic effects than with an outer obscuring
region. It may still be possible that the dust has an important role in the low
activity phase when it is coming inside of the BLR, making a dusty BLR. In this
way, it causes a decrease in the ionization and recombination rates.
