This scanner
Guest list
CSV with columns for number, name and batch (email is optional). Save Excel or Sheets files as CSV first. Importing again keeps check-ins but replaces names and batches, including any you edited here. With a list loaded, tickets not on it are refused.
Records
Clear all data
Deletes the guest list and every check-in on all scanners. This can't be undone, so export first if you need the records.