You cannot make this type of change on an existing paycheck while Lock Net Pay is selected. To make this change, you must first select Unlock Net Pay.
Important: Making certain changes on an existing paycheck can change tax and liability amounts, wage base, and net pay. This can result in additional payroll liabilities and may require you to amend payroll tax forms. Be very careful when editing paychecks that have already been saved in QuickBooks and issued to the employee.