I was wondering how to predict the location of the operating point of a variable speed compressor changes based on control set point.

For example, consider a compressor running at its rated point and controlled via discharge pressure control. Assuming the operator decides to reduce the discharge pressure control set point from 100 bar to 95 bar. How will the compressor operating point shift considering that inlet conditions do not change initially?

Will the compressor speed reduce thereby reducing pressure and flow hence the point will travel down and to the left? Or will the operating point go straight down mainting same flow but reducing discharge pressure? Or will the compressor speed not change at all but the operating point will go to the right side along the performance curve?

When to know if the compressor speed will change and when to know that speed will not change but the point will travel along the curve?

Thanks in advance!!