How to add the RRSP to an Employee?

Hello,

We have a situation where an employee received their final payment in PP18, but the RRSP (Registered Retirement Savings Plan) contribution was not included for this employee. The three highlighted items in yellow should be allocated for RRSP. Now, we need to reverse the employee's pay and reprocess it. How can we designate these three highlighted items should be for RRSP, and how can we add the RRSP contribution for this employee?

Thank you so much in advance.