Thanks for reaching out to the Community, Library Inc. I'd be more than happy to guide you through deleting payroll clients.
They can be removed from your subscription through the QuickBooks Payroll Account Maintenance screen.
Here's how:
I've also included a detailed resource about removing clients which may come in handy moving forward: Change your Employer Identification Number (EIN) for payroll.
If there's any additional questions, I'm just a post away. Have a wonderful day!