AD7992: Blocking conversion or register update in Modes 2 and 3

I would like to be able to "freeze" the value in the conversion register while in Mode 2 using a signal local to the AD7992.  Will holding ^CONVST high prevent the start of conversion that would be initiated by an I2C write command (or at least block the update of the conversion register)?  If so, is there any downside to this approach, other than that the converter is powered up while ^CONVST is high? Can the conversion register be read while ^CONVST is high?