To edit existing payscales without adding a new effective date:
Go to Setup and click Settings.
Click Module Settings and then Payroll Settings.
Select Pay Grade and Payscale.
Click the arrow next to the title of the negotiating body.
Select the existing effective date you need to amend.
Click the Payscales tab and scroll down to click Edit.
Change the values for the existing payscales by editing the FTE Salary or Hourly Rate field (depending on how the negotiating body has been set up).
Click Save.
Choose to push out the changes with or without approval as needed and click Save.
This will generate new salary lines with the effective date selected to the employees on this negotiating body. If they already have a salary line with the same effective date, only one will be active depending on which one is approved.