If you've processed an employee as a leaver but didn't pay them their final pay, destroy the P45, then remove the Leave date from their record and process their final pay.

Pay the leaver their final pay

1. Double-click the employee.
2. Click the Employment tab.
3. Remove the Leave Date.
4. Click Save then click Close.

You can now process their final payment, update records, then make the employee a leaver and produce their P45.