You can change the pay to reflect the new start date for an employee, by following the below steps:
Find the employee using the organisation search then click Payroll tab.
Click Pay then click into Pay history.
Open the top salary line.
From here you will be able to amend the start date of the employees pay.
📌Note: You need to manually type the effective start date instead of clicking the correct date. Once this has been complete you may also need to refresh the rota for the employee to show.