Some field names and drop-down options in registers cannot be edited if they are being used within a Privacy Assessment, i.e. either system templates or assessments created by customers. 

After clicking the 'Pen' icon within Register Management, you may notice that some field names are 'greyed out', which means this field is being used in a Master Record Privacy Assessment.  You may also notice that clicking on the drop-down options will not allow you to edit them; however, you can delete drop-downs as long as they have not been responded to within an assessment. 

If the field has been added to an assessment by a customer (non-system template), deleting the field/question from the customer-created template(s) will allow the field name and drop-down options to be edited.