Are you recording it in multiple rows? If you don’t want to go the Trebuchet way, you can:
Create a template joining the user’s email/ID with the event ID in the Events table, assuming you’re writing both of these fields in the destination table.
Do the same template column on the destination table’s side.
Create a relation from the Events table to the destination table using the 2 columns above.
The button to confirm or reject should write a new row to the destination table if the relation above is empty, else you do a set column to set the chosen value to the existing row in the destination table.