Two sections, edit patient case data (unit number and/or referral source), or requests details (specimen, trial, referrer, etc). Patient case data may belong to more than one record, whereas request details are specific to one request. Also the retrieval method for referrer depends on referral location so a change to both referral location and referrer requires the location edit to occur before the referrer edit.
Edit patient case data will bring up an option to specify whether the change is specific to one request, or is to be applied to all matching records, where there is more than one record attached to the case.
If current unit_number = 'UNKNOWN' and is being changed to a known value, default is 'all' in 'Apply change to' section, on assumption that current value is valid for previous requests for current patient/location.