Edit a Pay Schedule

Go to Setup > Pay Policies.
In the Pay Schedules section, click Edit.
Make your changes and click OK.
At the Pay Schedule Confirmation page, review the upcoming pay periods and pay dates.

If they're correct, you can edit the Description to distinguish this pay schedule from others, and then click OK.
If they aren't correct, click Back and make changes.

Since you're editing an existing pay schedule, you don't need to make any changes for employees who are already paid on that schedule.