I have used the CCP4 program "re-index" to add a screw axis before (e.g. P6 -> P61, P2 -> P21), but never to change the point group (e.g. PG4 -> PG422).
I initially re-indexing the reflections without error, but refmac5 later complained that there were too many reflections for the given asymmetric unit; upon closer inspection, only the space group had changed, but the number of reflections had not decreased as expected. Am I missing something obvious here?
