Why can't I change the calibration type on my HI 1756WS?

I have communications to my HI 1756WS module, but when I try to set up my calibration type in the parameters it will not change. Why can't I change the calibration type?

The HI 1756WS and HI 1756-2WS calibration type is a read only parameter you cannot change it. It is a designation of the last calibration type that was done.