3-phase 380 V to 3-phase 230 V
Figure 1. Coloured up version for single-phase 230 V + N wiring.

It appears from the wiring diagram that you can just connect L3 to neutral instead with no internal modification.

The only concern should be that the components' insulation now has to withstand 230 V instead of \$ \frac {230}{\sqrt 3} \ \text V\$. You should check, if possible, that they are rated for that.