The option to directly swap or offer shift in between employees is unavailable in QuickBooks Online (QBO) US Payroll, hello248.
In QBO, employees needs to contact their admin or payroll manager for approval.
Once approved, the admin or the manager will manually adjust the schedules for the employees involved to facilitate the shift swap.
I'll share this article for further information: Manage Shifts.
Feel free to reply to this post if you need further assistance.